The definitive identifiers for a native Trade Gun are a curved dragon shaped brass plate on the left side of the action. The classic Hudson Bay trade gun was made by Grice and has a seated fox as its trademark. The trigger guard is also larger for use in winter. Finally, I recall the cheapest but most practical buttplate was not brass, but a piece of bent sheet iron.
I don't own one, but I had to learn a bit when I was offered one at a gun show. Those points have stuck with me.
The lock certainly suggests English manufacture and late flint period. The engraved butt plate, cast in engraving on the lock plate and a fore-end cap suggest an upgrade from any average trade gun so maybe a fowler or "Chief's Gun"? The few Chief's Guns I have seen did not have the over-sized trigger guard or dragon side-plate.



























