Neat gun
I'll throw this out and see if it sticks to anything
Certain things say "French " to me.
The stock profile bears a resemblance to a couple in Lenk's book.The lock looks it to me also [see plate 87]
the buttplate also is very close to the one on plate 91
And the TG bears a close yet plainer likeness to the one on plate
88
All styles date around to the 1720's give or take
As to some of the other features I am open for suggestion,some are clearly Germanic.
i guess that's what happens when your country borders other gunmaking countries.