This is my first thread after being fascinated with reading here for some time now. I’m hoping some of you may be able to offer some wise counsel on an Army Navy CSL shotgun of mine. It’s a 12 gauge side by side box lock extractor which I believe to be fairly early. Glascow has no records on the guard number, and it is NOT nitro proofed. What does not seem to fit though is that the barrels do not appear to be Damascus, and the proof marks seem as if it has perhaps been proofed at different- though both early- times.

Is it possible that a sxs box lock extractor might have been made with fluid steel barrels in the late 1880s?