Hi,
There has been some discussion recently that the barrel and action were browned. There is some evidence that the pattern 1776 muzzleloading rifle has a browned barrel and Jesse Melot says he saw evidence of browning on the Ferguson rifle in the Milwaukee museum. However, there is no evidence of it on the Morristown gun, which I have examined and was also examined in detail by Ernie Cowan and Richard Keller. The Milwaukee gun has markings filed off and evidence of having been diddled with. However, the Morristown gun has a gun metal (bronze) screw plug whereas the Milwaukee plug is steel and so are most surviving Fergusons made for officers, EIC, and sportsmen. So the answer is probably do what you want. You can probably justify browning or not browning. I would not brown the lock, rather case harden it and leave the temper colors or polish them off. There is a recent article in Muzzleblasts about the Ferguson, which describes browning the barrel, action, and lock but the author is very unconvincing and relies entirely on one person's opinion. Lexington, do what you want and if you brown the barrel that may be correct. We just have no conclusive evidence that it was done.
dave