I'm pretty unconvinced by all of the supposed "Bob" Clemente signatures.
I think its pretty easy to forge a signature, and the memorabilia world is rife with fakes that have been identified as authentic by the "experts".
I am also unconvinced by the 1967 Topps card's supposed "Bob" Clemente signature. We are talking about a company that routinely airbrushed and tampered with photographs.
At least one person doesn't even think it says Bob, but rather "Rob" which adds another wrinkle.
I am also unconvinced that Topps was overtly racist or had malevolent intentions in calling him Bob. On the back of both the '57 and '62 cards, for instance, he is referred to as Roberto. I think Topps calling him Bob was probably a sloppy oversight.
What we can say for certain, is that he unequivocally told the Press in 1955 that he wanted to be called Roberto Clemente (see post#34). Whether that changed later in his life, we may never know for sure.