That's insane - thanks for posting Matt! Looks like he could have done 3 to 4 reps. I think Thor is going to be the first guy to break Eddie's record. He might do it this year at the Arnold. In one of his videos he says he thinks he'll do 500+ this year. Looks like he bulked up quite a bit also since he slimmed down a few months ago. He's gotta be 440-450ls now. His stomach is not too big either.
That said I think Eddie could have gone 510kg the day he lifted 500kg. If you look at videos of that lift you'll see that he had a little more left in the tank. But it almost killed him. So his muscles could handle it but not sure his heart would have taken that. His pulse was over 200 and they could not even read his blood pressure right after the lift.