That is a very early TC Hawken. The frizzen and cock are case hardened. Some people claim that the newer (Black) frizzen and cock (with a different angle), are better. TC replaced mine, with the newer. I offered to pay, but they replaced it free. Birchwood Casey makes a brass black, that will make the brass antique patina. 44/40 cold bluing will do the same. I recommend, to those who "can", learn to completely disassemble a lock. You will live a happier life.
Your rifle should have a slotted touch hole, a lot of people replace them with TC's newer, allen style liner. Suppose to improve ignition. I put a little anti-seize on treads. Same threads as a nipple, and I treat it the same, and remove it during cleaning. I just snug it, the lock sets against it anyway. I remove the lock every time I clean the rifle, and check screws, spray with oil and remove all excess. That rifle, has a barrel made by Douglas, or other major barrel maker, and should have a spade or maltese cross stamped on the bottom of the barrel. Should be a good shooter, mine is. That TC scope is an antique now, and you might be able to remove it, and find the original replacement sights. The hole spacing was different on the early Hawkens. So beware if you are buying a rear sight.