James, I cant say for sure what the markings were, on the boxes or ammo itself, as its been a long while since I shot any.
Some Ive shot did have black tips, but most were unmarked. Most of the packaging markings on the outside of the crates were in English over the original language, be it painted or a label, and said "not for use in pistols". We shot a ton of it back in the 80's and 90's as it was usually cheaper than most anything else when you found it, and we were shooting it out of SMG's.
Interestingly enough, the Spanish ammo I was shooting in my MAC that trashed the upper in the pics above, was marked in Spanish, " ......Schmeiser Y Pistola Parabellum". Then again, from the tank like Star pistols Ive owned over the years, they probably could have handled it.
This is a box of the Spanish stuff. I still have a couple, just never got rid of them over the years.
This is some Egyptian stuff that was hot and corrosive. It came in 36 round boxes, which happens to be what the magazines hold in the Port Said copies of the Swedish M45 the Egyptians fielded. This stuff is actually nastier than the Spanish, and would rust anything you shot it out of overnight, if it was humid and you didnt clean it right away when you got home.
As 44AMP said, its likely the countries that issued it during war, werent to worried about occasional or emergency use in pistols, since they were likely not really used all that much, and werent getting a steady diet of it.
Another possibility here is, some of the ammo released as "surplus" was actually nothing of the sort, and was refused as unacceptable, and ended up in the civilian market, and simply marked for SMG's as a liability disclaimer, so people wouldnt shoot it in pistols.
We got a bad batch of 7.62x51 (if I remember right, it was CBC head stamped) back in the 80's out of SGN, that was recalled soon after, due to guns shooting it blowing up. It was sold as "surplus", but Im not aware of any 7.62x51 being loaded "hot" for issue use, so we always assumed it was a bad lot that was refused and got into the system.