Drew, your thought of export is interesting. I believe current law is that both the exporting and importing country require proofs, but I have no idea what the practice was back in the mid 19th century. Perhaps, as you suggest, it was manufactured by Francotte for export to a country not requiring proofed barrels. I did get a message from Mr. Nash of Ontario who also has an unnamed firearm with marked Francotte barrels from the 1870's. Thanks for the information. Tony