no of course not. But let's be honest he wouldn't get credit by some xenophobic and racist fans if he would beat prime Ali, Foreman and Jesus Christ in the same night via KO1.
GGG won't get credit for beating Cotto/Canelo (Floyd leftovers), Froch (Ward leftovers) or even Ward (he was inactive for too long).
I think Pac career is a good answer to you question. The guy had a phenomenal career but lots of people still don't give him credit and treat him like a bum. It doesn't matter who you beat to the people that irrationally hate you. And in the sport of boxing you will eventually lose. Or if you don't lose like Floyd people will say that you ducked everyone. And not Lemieux is not a leftover. It's enough to watch one of his recent fights. The dude punches with mean intentions real snap and has solid fundamentals. His stamina seems a lot better. He will be a major player in the division no matter what's the final result this weekend.
Pacquiao is a great example of how losses doesn't have to ruin a career. He's fortunate to have a dedicated fan base that makes him profitable no matter what. I believe GGG is slowly but surely building that kind of fan base.
will mayweather get credit for beating torrencempo's left over? See it does not work like that if we go by that its a long road the reality is fighters improve and take losses early in career in davids case it was more of getting gassed out then anything else
if GGG could use a time machine to bring prime Hagler back today, fought him and beat him, the haters would say the time machine drained Hagler, Hagler is a bum or GGG fought SRL's leftovers