Victor history

I have been enjoying learning about different older traps lately and am having trouble finding a good time line to the different features of Onieda traps. I have been getting my hands on a few of the gov't traps and in the process have a few cheaper ones that are close to the old 3n's but are not quite. They have cast jaws, nut in the middle of the bottom and have a big stamping of victor on the pan. Any ideas as to age? value? and history to add to my understanding?

Another trap has a SG stamped in the jaw. Any idea on this? I'm guessing it is someone's personal stamp but not sure.

The square rivet on the bottom of the frame lets you know the Onieda Community was the maker of those traps.