Kofi Langton was a boxer based on a real boxer featured in Rocky V. In Rocky V, Kofi Langton gets knocked out by Tommy Gunn in the montage showing Gunn rising through the ranks. If you watch the marquees during this montage you will see Tommy Gunn vs Jeff Langton on the marquee before Gunn and Langton fight.
Kofi was played by Jeff langton, who also trained and coached Morrison on set. He is a real boxing trainer and corner man, though Kofi looks nothing like Jeff as he is white and Kofi is black. Although they misplaced Langton's name with another boxer's sequence. This has caused some confusion over the years. If you youtube Jeff Langton you will see his boxing gym and what he actually looks like.