The gun was originally proved 1896-1904, and clearly marked CHOKE
Reproved 1955 if the date code is 'FB'; 1964 if 'PB' with bore .729"
The original 12 would be .729 - .739 so likely not honed
Yes, crolle damascus barrels

You might ask the seller to chalk or grease pen the top rib to get the words

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