TC,
That's a cool find! I'm no expert in anything, but that stock shape and rifled barrel make this a Jezail, which is native to Afghanistan and maybe bordering countries. I'd reckon that the missing lock was a repurposed British musket lock or something similar. Snaphaunces are more typically found on North African guns. Aside from coming from Islamic cultures, lots of stock decorations, and being muzzleloaders, the commonalities between Jezails and other so-called "Camel guns" end, as it seems based on my sources (youtube, posts in this forum, and some internet articles) that Jezails were the only Middle Eastern civilian arms tending to be rifled.
There were also matchlock jezails, but that would have the type of matchlock commonly found in India, where the serpentine mechanism is completely within in the stock.
These were used extensively throughout the 19th century by Afghans fighting British troops, and to useful effect. There have been analogies between the Jezail and the American longrifle, since they are both long, muzzleloading rifles.
There's a good Forgotten Weapons video about one of these on YouTube.
There are other members of this forum who are much more knowledgeable than I about these sort of things. I'm sure one will add to this thread soon.
Best regards,
A.J.