My first thoughts mirror Eric’s very strongly. I’ll list a few, and am not claiming absolute cast-in-stone ideas. OLUT and John are also on point. I would really like to examine this interesting enigma rifle in hand.
1) Seems to be a much used stock with too recent unworn-looking carving.
2) I bet the larger 8 grooved bore is straight rifled, as mentioned, and the 7 grooved bore is twist rifled.
3) I suspect the barrels are mis-matched old barrels living a second life in this possibly mid 20th Century “antiqued" stock.
4) I wonder if the scrip-signed barrel was stamped with the same name in the re-working period by a re-builder wanting to clarify the original maker.
5) The extremely short back action lock is VERY unusual. I want to see its innards. The shorter-than-usual mainspring might be rounded with a really large radius (possibly old) and not a “V” mainspring, or a (choke) modern coil spring one.
6) The flat cock combined with a rounded pan makes me think incorrect reconversion at least, but the butchered groove in the stock above the lock for relief of the cock-arrest shoulder makes me wonder about “retroversion”, meaning turning an originally percussion-made gun into a fraudulent flintlock. Please post a photo of the top front of the lock from above with the cock at full cock to show where the cock arrest shoulder rests on the top of the lock when fired.
7) The “lock screw” doesn’t seem to line up between the lock and side plate, making me wonder if the heads represent wood screws. I really want to see the inside of that lock!
8 The trigger guard bow has a soldered front “trigger-like” extension like David Boyer of Orwigsburg made on some of his percussion swivels, but the grip rail looks later than flintlock era and maybe is mis-matched brass.
9) I really like the patch box with its "asymmetrical symmetry" of the side plate piercings and its engraving.
Summary: I suspect this is a composite rifle with some old and some new parts and an “aged” 20th C stocking, or a 19th C stocking with 20th C carving. May we see the inside of that interesting lock? And I would like to read other opinions as well.