hi again guys, just read on wikipedia that the reason why Tuco calls Clint 'Blondie' in GBU is because it is a Mexican nickname for a White American, something that i dont even think Frayling picks up on. This would serve to answer my long-held confusion regarding this, and also Angel-Eyes' order to his minions: "I want that blonde alive", he was couching it in those terms.
light brown
Actually...his hair is more of a sand color. Shoulda called him "Sandy".
"I want that Sand alive"
I think he's called Blondie not because he's actually blonde, but because he has lighter hair and skin that many of the other characters he comes across.It could be just some sort of a joke, or another name for a white person, or just a silly nickname.