searching key words "wwe real steel" brought me here. i was curious about the exact same thing, but the reference that really got me marking out was the reference to where Atom hails from, and it was cited as "parts unknown", which is exactly how The Ultimate Warrior and Kane (half-brother of The Undertaker) are billed in the WWE. Chris Jericho, at one point, even referenced it and said he's terrified of wrestlers who hail from "Parts Unknown."
Also, I'm pretty convinced that taking elements from prowrestling/WWE was intentional. I want to make it clear that I'm completely aware that the movie is about robot that uses a "boxing" style of fighting, but the element of gimmicks (dancing robot), baby face/heel competitors (Atom is cheered, Zeus is booed), the use of a femme fatale authority figure/valet, the father (money)/daughter(brains)/fighter(brawn) combo as dictating the shots in the league is like a reference to vince/stephanie/hhh management.
I think the technical parts are expressly based on wrestling, but the "drama", "entertainment" and "exhibition"/"showmanship" elements are all implicitly prowrestling.