Wouter, your suspicion was right. Source is Boxing News 4 April 1958, p6 - fight report describes him as "Sam (Esso) Lamptey", and this is backed up by Boxing News 7 March 1958 p10 and 28 March 1958 p12.
Therefore could you please merge the records for ID# 535818 and ID# 299285 and put one name as an alias for the other. Thank you!