I believe both R/R Animal and Jim the Anvil Neidhardt were as strong as their claims.
Neidhart had a huge power clean (I can't recall the amount) and could "hip-toss" guys across the ring with a great deal of momentum back in the early 1980's in Mid-South Wrestling. He had some legit throwing records as well, I believe.
Animal was one of the stongest wrestlers I'd ever seen. While I realize that pressing a wrestler overhead is assisted by the guy being lifted, Animal used to do reps, and a without knee-bend or momentum. He'd do it like a strict military press on purpose to show his strength.
At the same time, bench claims are bound to be over-stated, just based on the fact that everybody else is adding over 50 lbs more, except for the competitive powerlifters like Arcidi, Furnas and Kaz.