I bought a pair of 20-bores from a fellow. One is a "smooth rifle" according to the builder, but has no rear sight, which I consider the difference between a fowling piece and a smooth-rifle.
When I started building muzzle loaders, I asked Bob Roller for some advice on what to smooth and polish on a lock - he told me to polish EVERYTHING, front and back. So that is what I do with any lock I come across. These locks still had the casting gates on the cock top-plate, and were very un-finished. So, adhering to Mr. Roller's advice, everything got polished. And nicely browned with many layers of LMF. And lots of 0000 steel wool!
They look really nice, and the first one is back in the stock, ready to spark some fires in the tubes. Got no fingerprints left tho - all the grades of silicon carbide paper from 220 up to 800 will do that.
I really do like the look of the Queen Ann locks, and I have a nice pistol barrel - so, hunting for a smaller version of that lock. And I did take the "lug" off the bottom of the frizzen on the first lock, the second really needs to be annealed because the file just skates over the lug on the second one. But I am not good with hardening, so I plan to just let it be for now.
Used mink oil on a toothpick to lube the lock, as I kinda ran out of bear oil a friend had sent me. Hey, it's waterprooof, anyway!