Most of these are results from the Central Plaza Hotel that are on the site only as "Oklahoma City, Oklahoma". It would not stun me if there's other Smith fights from Oklahoma City which are Central Plaza Hotel fights, but i'm only listing the cards which get mentioned in a news source (I'm using Access World News / Newsbank)
Oklahoma didn't have a boxing commission from the mid-70s to 1995, if that explains anything you were suspecting.
The Daily Oklahoman has some old articles online at NewsOK.com, so you could do a Google search of that site to check into these things too.
3/1/1988 ( http://boxrec.com/show_display.php?show_id=25798 ) - Tradewinds Central Inn, Oklahoma City, Oklahoma (source: Daily Oklahoman, 3/1/1988)
5/31/1988 ( http://boxrec.com/show_display.php?show_id=17931 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 6/1/1988)
6/7/1988 ( http://boxrec.com/show_display.php?show_id=23696 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 5/29/1988)
7/19/1988 ( http://boxrec.com/show_display.php?show_id=53765 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 7/20/1988)
11/15/1988 ( http://boxrec.com/show_display.php?show_id=37869 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 11/13/1988)
12/6/1988 ( http://boxrec.com/show_display.php?show_id=52794 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 11/27/1988)
2/21/1989 ( http://boxrec.com/show_display.php?show_id=53761 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 2/19/1989)
3/21/1989 ( http://boxrec.com/show_display.php?show_id=25800 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 3/19/1989)
4/4/1989 ( http://boxrec.com/show_display.php?show_id=25801 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 3/30/1989)
4/18/1989 ( http://boxrec.com/show_display.php?show_id=25802 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 4/9/1989)
5/2/1989 ( http://boxrec.com/show_display.php?show_id=53759 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 5/2/1989)
6/27/1989 ( http://boxrec.com/show_display.php?show_id=456734 and http://boxrec.com/show_display.php?show_id=15284 which are the same card ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 6/18/1989)
7/11/1989 ( http://boxrec.com/show_display.php?show_id=44766 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 7/11/1989)
8/1/1989 ( http://boxrec.com/show_display.php?show_id=53758 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 7/23/1989)
8/15/1989 ( http://boxrec.com/show_display.php?show_id=42042 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 8/13/1989)
9/5/1989 ( http://boxrec.com/show_display.php?show_id=53457 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 8/20/1989)
9/19/1989 ( http://boxrec.com/show_display.php?show_id=50487 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 9/10/1989)
11/21/1989 ( http://boxrec.com/show_display.php?show_id=50294 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 11/19/1989)
12/12/1989 ( http://boxrec.com/show_display.php?show_id=37865 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 12/10/1989)
3/20/1990 ( http://boxrec.com/show_display.php?show_id=50292 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 3/18/1990)
4/17/1990 ( http://boxrec.com/show_display.php?show_id=52501 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 4/15/1990)
5/24/1990 ( http://boxrec.com/show_display.php?show_id=18012 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 5/24/1990)
6/21/1990 ( http://boxrec.com/show_display.php?show_id=37863 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 6/21/1990)
7/16/1990 ( http://boxrec.com/show_display.php?show_id=3306 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 7/15/1990)
7/31/1990 ( http://boxrec.com/show_display.php?show_id=25806 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 7/31/1990)
9/11/1990 ( http://boxrec.com/show_display.php?show_id=3385 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 9/9/1990)
2/1/1991 ( http://boxrec.com/show_display.php?show_id=53446 ) - Boxing Plaza, OKC, OK (s: Daily Oklahoman, 1/20/1991)
2/18/1991 ( http://boxrec.com/show_display.php?show_id=19315 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 2/17/1991)
3/1/1991 ( http://boxrec.com/show_display.php?show_id=25821 ) - Boxing Plaza, OKC, OK (s: Daily Oklahoman, 2/24/1991)
6/17/1991 ( http://boxrec.com/show_display.php?show_id=53431 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 6/17/1991)
7/30/1991 ( http://boxrec.com/show_display.php?show_id=43677 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 7/31/1991)
12/3/1991 ( http://boxrec.com/show_display.php?show_id=50285 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 12/1/1991)
3/12/1992 ( http://boxrec.com/show_display.php?show_id=50479 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 3/8/1992)
4/16/1992 ( http://boxrec.com/show_display.php?show_id=4353 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 4/16/1992)
6/12/1992 ( http://boxrec.com/show_display.php?show_id=4446 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 6/12/1992)
7/23/1992 ( http://boxrec.com/show_display.php?show_id=4524 ) - Rock City Cafe, OKC, OK (s: Daily Oklahoman, 7/23/1992)
9/15/1992 ( http://boxrec.com/show_display.php?show_id=43675 ) - Rock City Cafe, OKC, OK (s: Daily Oklahoman, 9/13/1992)
10/2/1992 ( http://boxrec.com/show_display.php?show_id=4641 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 10/2/1992)
10/21/1992 ( http://boxrec.com/show_display.php?show_id=43715 ) - Rock City Cafe, OKC, OK (s: Daily Oklahoman, 10/21/1992)
3/6/1993 ( http://boxrec.com/show_display.php?show_id=31366 ) - Tradewinds Central, OKC, OK (s: Daily Oklahoman, 3/7/1993)
12/17/1993 ( http://boxrec.com/show_display.php?show_id=179804 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 12/16/1993)
12/19/1995 ( http://boxrec.com/show_display.php?show_id=19128 ) - Central Plaza Hotel, OKC, OK (s: Daily Oklahoman, 12/10/1995)
Non-Oklahoma:
4/26/1991 ( http://boxrec.com/show_display.php?show_id=53435 ) - Mid America All Indian Center, Wichita, KS (s: Wichita Eagle, 4/13/1991)
5/30/1991 ( http://boxrec.com/show_display.php?show_id=53432 ) - Southland Greyhound Park, West Memphis, AR (s: Memphis Commercial Appeal, 5/31/1991)
8/6/1991 ( http://boxrec.com/show_display.php?show_id=53428 ) - Omni New Daisy Theater, Memphis, TN (s: Memphis Commercial Appeal, 8/7/1991)
10/1/1991 ( http://boxrec.com/show_display.php?show_id=53425 ) - Omni New Daisy Theater, Memphis, TN (s: Memphis Commercial Appeal, 10/2/1991)
11/2/1991 ( http://boxrec.com/show_display.php?show_id=18009 ) - Century II, Wichita KS (s: Wichita Eagle, 11/1/1991) - There's a Century II Auditorium and Century II Convention Center, and I think they're the same building. The source didn't specify if it was called Auditorium or Convention Center.
2/3/1992 ( http://boxrec.com/show_display.php?show_id=53405 ) - Allis Plaza Hotel, Kansas City, MO (s: Kansas City Star, 2/4/1992)
6/2/1992 ( http://boxrec.com/show_display.php?show_id=53402 ) - Omni New Daisy Theater, Memphis, TN (s: Memphis Commercial Appeal, 6/3/1992)
6/22/1992 ( http://boxrec.com/show_display.php?show_id=679263 ) - Allis Plaza Hotel, Kansas City, MO (s: Kansas City Star, 6/22/1992)
9/24/1992 ( http://boxrec.com/show_display.php?show_id=32434 ) - Mid America All Indian Center, Wichita, KS (s: Wichita Eagle, 9/24/1992)
12/7/1993 ( http://boxrec.com/show_display.php?show_id=43274 ) - Omni New Daisy Theater, Memphis, TN (s: Memphis Commercial Appeal, 12/8/1993)
1/4/1994 ( http://boxrec.com/show_display.php?show_id=41364 ) - Omni New Daisy Theater, Memphis, TN (s: Memphis Commercial Appeal, 1/5/1994)
5/2/1995 ( http://boxrec.com/show_display.php?show_id=19301 ) - Omni New Daisy Theater, Memphis, TN (s: Memphis Commercial Appeal, 5/2/1995)
3/5/1996 ( http://boxrec.com/show_display.php?show_id=19097 ) - Omni New Daisy Theater, Memphis, TN (s: Memphis Commercial Appeal, 3/6/1996)
12/2/1997 ( http://boxrec.com/show_display.php?show_id=28980 ) - Omni New Daisy Theater, Memphis, TN (s: Memphis Commercial Appeal, 12/2/1997)
3/15/1998 ( http://boxrec.com/show_display.php?show_id=16691 ) - Sycuan Casino, El Cajon, CA (s: Burlington Hawk Eye, 3/16/1998)
There's most likely a bunch more Memphis New Daisy Theater shows listed as just "Memphis, TN". A combing of the Memphis Commercial Appeal would be needed to verify how many.
