Don't believe #560 for Lou, atleast not a clean bench. I do think he could get into the low #500's, but not that high. I'm basing that on what other dedicated Powerlifters, Strongmen, OL'ers, and Track and Field guys were doing at the time. #560 was and is, a huge number. You'll see it today even with raw lifters, etc...... once they break into the low #400's, it's a big fight for every pound after that point.
I'm also grading it by the old standards, which would be feet on floor, head on bench, minimal arch, with decent press commands. Not the any-how style that most gym lifts get graded on.