Well Ray,.... I'm not having much luck.
I can't find an original lock on North West trade guns that are both,... flat faced and have the Germanic style contour of your lock's pan.
Your ramrod thimbles are typical of the various thimbles made over a span of 350 years, and are still available today.
Your side plate is a puzzler also,.... as almost without exception, (both foreign and domestic) North West trade guns serpent/dragon side plates had holes for the 2 lock bolts
PLUS a hole in the dragon's tail for a wood screw, in both types,... cast and stamped from sheet brass. The only exception for a (short style) serpent/dragon side plate similar to your's (that I could find), were on some Chief's Guns made by Richard Wilson in 1750-1770, and they had the typical small brass trigger guard bow (engraved), along with the engraved brass butt plates found on government contracted Chief's Guns.
From all indications,.... I'm gonna guess your trade gun was built sometime around, or, after 1960, mainly due to the unusual "step" in the barrel's breech area.
Are there any stamps/marks on the gun's barrel to indicate who may have made it, and have you had the barrel out of the stock to see if there are any "maker's-mark" on the underside towards the breech end?
Also,.... I forgot to ask if the tang bolt on your gun enters from the top and screws into the trigger plate, or if it angles up from the bottom (in front of the trigger bow) and screws into the tang. Looking at your pictures I'm guessing the bolt comes in from the top, which would indicate it's probably a replica of one of the later style North West trade guns.
A lot of replicas built around that time period were built by individuals using parts no longer available from today's parts suppliers, or were custom made.
The main thing is,........
DOES SHE SHOOT GOOD?