I know what it means, but there is no damage, it has probably been in my change jar for 2 years LOL. Incuse does mean to stamp, but the whole coin is stamped, also I can take more images, to left of the barrel and the second pane down on the window there is another spot that looked strange, you can't see it well with this shot, was using a 60mm macro lens, could try to back out a bit more to get both and lighting is a big factor on a shinny surface, try to defuse it more.