I doubt it. Even though he’d have a big size and strength advantage, Sergio was in horrible shape by then and his legs were gone. He also wasn’t a huge puncher at 160. I can’t see Floyd demolishing him the way that Cotto did but I CAN see him winning a wide decision
The version that fought Chavez Jr was already having issues with his knees. Mayweather would win a UD.
I think prime Sergio would actually be a bit of a wild card to beat a lot of guys around his weight throughout boxing history, even if I wouldn't favor him against any of the greats.
I mean Martinez did lose his belt to a defeated Mayweather opponent in Cotto. Cotto lost his belt to another defeated Mayweather opponent in Canelo. Theres your answer. I never got the sense Mayweather or Manny were ducking MW so much as all the big fights were at 147/154. MW wasn't bad it just wasn't as good.