I am sure you are right - there is evidence on the breach faces of a repair plugging, what would have been, the pin holes for centre fire. You have to marvel at the trouble some one has gone to to take a pin fire, remove the hammers, drill it to convert it to centre fire - abandon the project but then take the trouble to have the holes filled in to return it to a pin fire - less it's hammers. If you were going to hang it on the wall the holes wouldn't show from underneath. I'm afraid that I don't have any history other than it came from a dealer in Devon or Cornwall who considered it beyond economic repair.
John
