I hope you are right and I'm all wet. In these last two images though, I see what looks like fouling next to the nipple seat. I am only expressing what I have experienced in my own shop, and that is that if a rifle comes in with fouling on the outside, the bore is always in tough shape, especially at the breech end. Run a tight patch on a button jag down the bore with some oil on it so it doesn't get jammed, and see how smooth the bore is. Use a cleaning rod - not the ramrod. If it is buggered, your jag will get tight and you will have difficulty withdrawing a ramrod and jag. So a cleaning rod is the ticket. Good luck, and keep us in the loops please.