Everyone, thanks for all the great info. I'll give it another double-check for any further marks that may direct us toward the maker.

fallschirmjaeger - yes, it is a Gunbroker find. It caught my attention because I am a sucker for a lightweight 16ga SxS.

The first two photos are from the seller. The remaining photos are courtesy of my Fuji X-E2 with a Fujinon 60mm macro lens. The gun was hand held under fluorescent light in my basement.