Not sure what frontier scout you are referring to. The only one I know of is a ruger rifle but then what does it matter here.^Ok stupid question: what's the black crap on the hammer spur? I got a Frontier Scout with it and I assumed that it was factory and meant gun wasn't used much but why is it there?
Anyway on the hammer spur, it has to be the bluing as mentioned above. Why it had to be there in the first place where your thumb will destroy it both mechanically and chemically, is anyone's guess. Mine is, it looked good when new, and now is sort of like fading on the blue jeans. A noble patina. No worries.