This has been on the internet for some time now.
You are right about their genes. Imagine taking such an amount of dbol (up to 100mg ED) for such a long time! He had no gyno, no known liver issues, no bloat, ... wtf?
In his time there were no AI (like adex, letro), so it all came down to luck. I remember one of his friends ending up with gyno (the guy also played in Pumping Iron).
PCT was done via taper, because Nolva/clomid did not exist back then.