Isn't there a character creator that lets you choose your skin (and therefore see your "JC Denton") even before the game starts?
Hmmm, I don't remember that either—and JC is also sort of a meme with his default appearance (presumably), used as userpics on Youtube and elsewhere. So I guess many just picked the first look offered. Seeing as JC is considered very much a ‘blank character’, there probably wasn't much of a meaningful difference in the choice.