I was there in 1990. Flex and Chris Cormier were training daily, as was Aaron Baker. They were strong.
I got to meet The Barbarian Twins, had pics taken with them and Berry Demay.
Spent a lot of time with Mike Mentzer.
I watched a Mexican dude with a long pony tail, walk up to the squat rack cold and take 3 plates out, 315lbs. I thought "shit, no warm up". He was a big guy, big gut, not a BB.
He then proceeded to knock out reps on the standing press behind neck, one of the most memorable feats of strength I have seen.
Muscle Beach was closed and being rebuilt though.