I had a typo in my original post and tried to edit it, but they typo is still there.
I found a buckle stamped with SOLID BRASS, and I was wondering when they started stamping that into buckles.
Sorry for the confusion.
Creskol, that's a great question, and I don't know the answer, but I do know the solid brass buckles of the 1950s were embossed 'solid brass.' http://oldcopper.org/list.htm
Breezie