Dunno. I think it depends on the circumstances.
If one of my sons was standing with a group of white kids (quite usual where we live
) and I wanted to point out to someone which one my son was, I could say.
"The tall one,no not that tall one, the other tall one, no not that tall one the slightly shorter one, ok, the one in the blue top, no, the dark blue top, no, the one on the left, oh no, he's moved, he's on the right now, no, not that one, ok, the one with brown hair, no, not that one, the short brown hair, no, not that one... 
Or I could say, "there he is, he's the mixed race lad"
If he was the only one wearing a blue top, then I'd probably say blue top. because either would equally identify him from the rest of the group around him.