Dave,
Since the bore diameter was marked in mm (8.9), but the case length wasn't shown, I believe the drilling was proofed close to the 1911 improvements to the 1891 proof law being implemented. I would guess it was proofed in about 1912. Since it does not have a proof date or register number, it was proofed in Suhl, so it was likely in or near there. Since there seems to be no crown W mark on the right barrel but is on the left, the left barrel is the only one choked. Sorry, this doesn't help very much to ID the maker.
Mike