Daryl, that is interesting and yes I have seen something similar before. I think that the Proof House did occasionally make mistakes; not that they will readily admit to it! I have a damascus barrelled gun that went for re-proof to nitro and now has one barrel stamped 'sleeved'; which or course it can't be. I had a Thomas Wild hammer gun that was proofed but did not have the nominal bore stamped on it so that it was impossible to determine whether or not it was 'in' proof or 'out'. I have also seen the converse of yours and oddly enough on another Greener but this time a single barrel which was marked 2 3/4" and 1 1/8 ounce. It might be interesting if you send that photo to the Birmingham Proof House and ask about it. Lagopus.....