I don't love the stutter/stop at the top of the S, and the loop inside the u is pretty weird, but other than that the signature does tend to fit his mid 60's signing style.
McQueen is a signature I have looked at closely for years, someday when I find one that I am confident on, I will add it to my collection, but the cost is way up there, so I will not settle.
This sample real or not is not for me. Before you jump to any conclusion on this, I would wait and see what the other people here think.
Like I said, the overall autograph fits his style in a particular time frame, a few minor things about the autograph being different does not make it "not genuine."