BoxRec

http://boxrec.com/boxer/10795
Aged 51: Won the Australian Victoria State middleweight title against Jim Higgins (8 1 1)
Aged 56: Defeated Ike Stewart (20 12 2)
Aged 57: Defeated Joe Lee (5 3 1)
Aged 59: Defeated Dan Creedon (39 20 10)

Yes, but those are all pretty poor records and 1 novice with 10 fights and a novice with 9 fights.

Larry Holmes, at age 52, beat Eric Esch 65-2-3.... and Holmes, at age 42, beat Ray Mercer, 18-0... Mercer WON and DEFENDED a Heavyweight Championship in his 2 previous fights, against Francesco Damiani 27-0 and Tommy Morrsion 28-0 ... so Mercer should have won Holmes a World Heavyweight Title. At age 43 Holmes beat Paul Poirier 31-2... At 47 Holmes outscored Brian Nielsen 31-0 in Denmark, but was robbed of the decision.

At age 45 George Foreman beat Michael Moorer, 35-0 to win the Lineal Heavyweight Championship.