The thing about browning is that you want to only do the outside parts, its not a from what I understand not an early finish. A lot of gunsmiths polish up the lock then heat blue the outside lock parts (Except for the frizen & spring) This is not a protective coating though just a color change. You would'nt want to do this with the frizzen or spring because you would lose the temper and the hardness to create a spark. Either way no it won't mess up the locks if you do not like it it can always be polished off. The browning may tend to pit the lock a bit if you let it get carried away.