Last similar piece I seen was made ca. 1839 in St.Louis, Missouri. That family came from Switzerland if I remember correctly.
Sounds about right for the timeframe. I figured roughly mid-1800s.
It is the odd piece at an estate auction and I could only take a quick look at it. I didn't see any obvious proof marks except possibly a very small stamp at the rear of the top flat of the barrel that could have been some sort of crown/crest with a point/elongated diamond base portion.
No other ID marks that I can see at a glance.
The general restraint and precision of execution would sound more like a Swiss than typical German maker.
There is some light scrollwork on locks, barrel, trigger guard and buttplate. The wood is straight grained and very well inletted with a form that reminds me more of a early US plains gun than a cuckoo clock.
The patch box on the right side of the butt is wood with a slightly raised/carved thumb-hold at the front. It slides out the back with the lifting of a small metal button at the base. the base is a cut-out part of the metal butt-plate.
The checkering is extremely fine pointed and simple. even tho the finish on the stock has obviously been redone the checkering appears original and untouched. The metal is slightly proud of the wood. Some of the screws have some slight buggering (mainly on the buttplate screws).
The rifling looked more like two-step raised/pointed, almost stepped pyramid, lands with deep grooves. The front sight has a small gold/brass bead.
The gun looks like the prior owner maintained it in a usable fashion and it wasn't too badly handled prior to that. The set trigger is a wonderful thing.