Hi Alexender,
You sure have found another remarkable early firearm!
As the touchhole is on the right hand side and is already surrounded by a rectangular pan shaped trough, and as the rear barrel plug already has a small square sort of tang, I would atribute the piece to the early 16th century, so we really are very close in our minds!
The stock may well be the original.
Where is this piece preserved? Could I have some high resolution image?
I attach my own photos of a very similar haquebut in the reserve collection of the Swiss Landesmuseum Zürich, the wrought iron barrel struck with a Nuremberg workshop mark, the pan probably a working life addition, the stock of comparable shape and stamped with
the date 1519 in Gothic cyphers. Please note that in the 15th and early 16th centuries, the cypher 5 often looked like a modern 7 but the Gohic numeral 7 actually looked like this: ^
Best wishes,
Mikhail