No they wouldn't. Bodybuilders back then had real work ethic, trained hard and trained right. Today's bodybuilders use copious amounts of drugs to compensate for their lack of hard work in the gym.
We tend to romanticize that era too much as though they didn't take shortcuts.
Not true.
They used every shortcut available to them. Everyone trained like Arnold cause he was the champ. Only Mentzer being a notable exception.
If they could've gotten their bodies to 285 shredded they would've but they couldn't.
They pushed their bodies are far as they could then.