I agree that unique patchbox finial is similar to Carl George's work, and it does have a later Berks like trigger guard. But the flat comb and hard knuckle are not the usual Berks County stock profile, albeit seen more often in later guns. I see it has the brass sliver above and below the lid itself---another rarely seen Berks County trait - except with Carl George and some other George family gunsmiths (Henry, Carl (Charles), Jacob and Jacob, Jr.) So even though it does not scream "Berks" - I also lean toward it being made by one of the family George (aka Gorg) gunsmiths who moved away from the more typical Berks "Roman nose" profile - but which one?
The heavy target barrel would be a good project to remove and see if a name is underneath. The George's used a lot of barrels from Sholb and William Pannebecker II, which might add some weight to a George family attribution.
Patrick Hornberger