Any idea when punching with a closed fist essentially became accepted in American wrestling?

Over here in Europe we were considerably more stringent against it even way into the 90's, but obviously in the Americas it was more prevalent

I was wondering when it just kind of became allowed seeing as technically punching with a closed fist is illegal? The 70's maybe?

​I think it was pretty much Bruno who made it an acceptable part of the WWF landscape, although clearly Jerry Lawler specialized in punching people and making it look real.  So yeah, I'd say the 70s.​