OK, yes that's the piece that he wrote up in MB. I'm pretty positive it's a German gun and Bill Kennedy (rip) thought the same. I'll have to try to see if I still have a copy of the article; I'm pretty sure, going from memory, that at the time he wrote it, he or someone was positing that it was an early Angstadt. I very strongly doubt that, even if it is in some way American.
I really do not believe a rammer on a rifle prior to the latest 18th or more likely early 19th century would have been spiral finished. I think it can work aesthetically, imho, on certain rifles, but I think you need to consider the big picture before deciding to spiral lest the piece just end up looking too crazy.