In Chapter Two, how is the man who gets onto the elevator with Will described? How does Will find out he is Buck?

The man who gets onto the elevator with Will in Chapter Two is described as being light skinned, with short hair, and wearing gold chains. When Will feels the man looking at him, he asks the man what he wants, and the man turns around to show the back of his shirt with a picture of him that says, “RIP BUCK YOU’LL BE MISSED 4EVA” (79). Will then realizes it is Buck.