Is it on video? I find it odd I can't find it neither on youtube nor the rest of the internet. That would shatter the world record. If he did do it, it's probably half rep and less, when does ronnie do anything full range? Deadlifts, that's prolly it.
No idea if it's on video and his form was impeccable. I have a very clear memory of that day, because Jim "the Iron Bull" Palechia also entered this unofficial bench contest. There was a lot of hype leading into it. At the time he was known as the world's strongest "power-bodybuilder".
Anyone could enter this contest. People off the street were walking up and taking their turn. No warm ups, no bench shirts, elbow braces, etc. You just walked up and did your best. I remember Frank Sepe got like 22 or 23. I got 21. There was a big crowd there. Finally it was "the Bull's" turn. For his turn, he needed all sorts of prep time. He had to warm up, he needed special music, bench shirt, writ-wraps, etc. The anticipation was building. How many reps might he get!? He finally got under the weight, took the bar of the rack and did his 1st rep. It came halfway down about 5" from his chest and he started back up. He did like 12-13 more like this and then racked. HUGE let down. Everyone was like, this guy's a joke.
Then, Ronnie stepped in and banged out the 75 reps with everyone counting out loud. It was awesome.