It's clearly real. There is definite bar bend, and also, why would someone put the extra 5 and 2.5 pound plates on each end to bring it to exactly 600 ... if it weren't real? Besides, he is gigantic and obviously using.
Still, this effort puts him in the upper scale of raw (but gassed) benchers. I have always said, the greatest pressers, on drugs, move between 550 and 650 pounds.
A dude like Mendelson (715, no pause) is a true freak of nature.