Yeah, it was a thing, and thanks, Hawkmoon.
I don't think it's possible to pinpoint when earplugs stopped being wimpish (and hence "unmanly") and things changed to a general acceptance of hearing protection, but it seems it noticably shifted in the early or mid- 1970s. You started to read about "permanent damage" in the gun rags.
I know it was about then that I got myself a pair of custom-molded earplugs from an audiologist. One of the touted advantages were that they were not obvious in wearing.
They were pretty comfortable but pretty expensive, and after I lost one in the creek, I got a pair of "valved" plugs, where the pressure wave of a shot would close the valve, thereby saving your eardrums. Supposedly. They sorta worked, but I quit using them because the valving system springs "boinged" with every step or sudden movement.
Very annoying.
About then I started up in competitive shooting at regular ranges (as opposed to the National Forests or the Grasslands) and started to see regular earmuffs appear at the ranges. I remember when I was assigned to the pits, I was wondering how come everyone was wearing earmuffs way back here since we were 300 yards from the firing line.
When the first shot over the target pits generated that supersonic crack, I realized why. It was about as loud as a .45 going off without hearing protection and it wasn't long before I stuffed rolled up tissues in my ears. Crack! A quarter second passes, then Boom.
I still remember tiny pieces of the target fluttering down in the sunlight.
So yeah, it was a thing.
Terry, 230RN