I prefer, but don't need (meaning if I like the rifle I can live with a different finish) a rifle finished "in the white" for lock and barrel. I like a natural patina..., for my rifles and my trade guns. My persona as a civilian is an inn keeper [an "ordinary"] who hunts from time to time for hides..., and I'm nearer the frontier by far, rather than more settled areas, so the cheapest rifle for me would have a minimum of hardware and have been left without a finish (imho).
I prefer brass mounted rifles, though I have a steel mounted .40 that I also left the hardware to patina in a natural manner. One can speed the process by using an acid to cause discoloration of the steel, short of actually browning it. (Mustard works very well for this.)
As for the brass I buy it shiny, and then let it dull over time.
For military muskets I like the lock and barrel polished, but not "armory bright"..., the steel should be a dull gray with some staining, though no rust. It should not shine like a chrome bumper on a vintage muscle car.
I also like browning as a second choice. However, I've found it's tough to find folks who do a proper browning (as far as what I was taught was the proper browning). You see, I often find very nice rifles that were not polished before browning. Sorry, but browning a lock that still has the surface from being a cast part (when the locks were not cast back then) is what I consider a huge mistake. It doesn't make them look more "authentic", and not polishing the barrel before browning doesn't help the barrel either (imho). The steel should be polished, and THEN browned (as I was taught that was what was done back then)..., but that's extra, grunt work for some builders. Oh well, I'm just one "buyer" of many. So..., my one browned rifle, had a polished barrel and polished lock BEFORE it was browned. :wink:
An actual charcoal blue is very nice too, and would be my third choice. That may be simply because so few builders that I've found do such a finish, or so few did it when I was in the market to buy. I don't own any rifles or guns done with a charcoal blue, but I've seen several, and it is supposed to be an authentic finish for the 18th century. I have seen it very well simulated by using chemical blue, then "rubbing it back" to get a very similar finish. An actual, modern blue, hot or cold, no thanks.
Oh and I've seen a couple of factory rifles that were Parkerized. No foolin', modern Parkerized. They were both give aways from a widow to the late hunter's neighbor. He kept good care of the bores in both rifles, but ignored the outside of the barrels a bit. Rain and perhaps a little blood will really pit the outside of a barrel. Even when polished some, there were still obvious imperfections, so since they shot very well and were only going to be hunting guns..., he had the barrels Parkerized. An interesting solution..., but not for something historic eh?
LD