While it looks like it was probably originally built as a double rifle due to the reinforced frame, I am wondering if it has been rebarreled for some reason. You can see the band of engraving which is doing a not so good job of concealing a rather prominent sleeving joint. The barrel blue also looks to be a bit darker ahead of this joint.
I would do some homework to try to determine whether the gun is original, or if it has been sleeved, rebarreled, or perhaps even built on a shotgun action. I'm also curious when it was built because the engraving looks laser cut.
