I have several BACO model 70s and am interested in knowing what some of the differences in proof marks may mean. The PW in an oval on both the receiver and barrel on the left side is most common. However, I have a South Carolina made Supergrade that has the PW in an oval on top of the barrel only and nothing on the receiver. Why the difference? Also, the bottom metal is all steel as supergrades are, but it is not stamped as such on the floor plate. Just curious as to why this is so.
