Very cool. I don't doubt the stars at all.
I'd say it was around 1760 or so. Dating German guns can be difficult. Putting locations on them can be even more difficult, but would say that it was from somewhere relatively near the Main River. The Star is "der Fraenkischer Stern" and was used on guns made along the Main river from Franken to der Pfalz, and a little bit north and south of the river. If I were to further guess, I'd say it was from somewhere just south of the Main. The "exhuberant" carving has the feel of a more Southerly gun.
The floral carving around the lock panels is very unusual. In fact, I've never seen anything like it.