Mayweather has NEVER been dropped, 19 years in the game. Yeah he has a granite chin. Wilder too, very good chin.
I don't know about Wilder, Floyd has a very under rated chin, but IMO you're over rating it. He doesn't get hit enough to really assess it.
??? he's been chinchecked so many times in his career Chop Chop, Mosley, Zab, Maidana, Marquez, Canelo, Castillo, Hernandez Never ever dropped
Zab knocked him down but got robbed. Blood tested old man Mosley almost had him out on his feet, imagine prime roided Mosley? Floyd has a good chin, this "iron chin" talk is a myth though.
as well as Chavez, Augustus, Ortiz, De La Hoya, if he was chin deficient, one of these guys would've gotten him out of there.