I have a small supply of vintage hammers from guns scrapped in the UK (25 or so). I am bringing them all to the Southern SxS in Sanford NC at the end of the month.
There is alot of variation in the hammers. The last 2 times someone needed a hammer, I had them mail me the good hammer or bits of the broken hammer. No promises, only a fair try to find a match.
PM me if you want to try or meet up in Sandford.
Are you also needing a hammer screw?

Joe in Charlotte