The rifle in the original post looks a lot like one of the J. Henry & Sons "Treaty Rifles" to me, although it does have a few differences. The triggerguard finial is atypical, as is the full buckhorn sight. However, most of its general features resemble those of the "Treaty Rifles." This one is in the Wilson's Creek National Battlefield collection:
Most were in smaller calibers, .36 to about .44, based on the ones I've researched. Most seem to be mounted in brass, with some in iron. Most seem to have barrel key escutcheons, but not all. Only a few have capboxes. However, the common features seem to be a walnut halfstock with a rib under the barrel, a "snail" type bolster for the nipple, double-set triggers, and a cast pewter nosecap.
Here is a better image of a typical "Treaty Rifle," with a better view of the triggerguard:
The Leman trade rifles I'm aware of had maple stocks, a different type of grip rail or spur on the triggerguard, and usually a single trigger. The Lemans were available in larger calibers, too. I know Green River Rifle Works marketed a halfstock Leman rifle which was supposedly based on an original, but most of the Leman "Trade Rifles" you see are fullstocks.
I don't think we are exactly clear on how these J. Henry & Sons Treaty rifles were distributed. A lot of them have one or more letters, usually "US," stamped in the wood aft of the triggerguard:
It has been suggested that these were provided by the US Government to the "reservation Indians," referring to the eastern tribesmen who had been forcibly removed to the western reservations. By all accounts, the Shawnee, Delaware, and Cherokee people of the Indian Territory preferred rifles to smoothbores. This is documented in the literature even before the time of removal. Josiah Gregg referred to these people as "frontier Indians," and he and most others distinguished the native plains tribes as "wild Indians." The reservation people frequently clashed with the native tribes over hunting territory.
You also see reports of these rifles being used as treaty gifts, specifically the Fort Laramie Treaty of 1868. In that case, the rifles would have gone to the "wild Indians." The general assumption is the calibers of the treaty rifles were kept small so they would be less effective as weapons of war, but would still serve for hunting. Whatever...
These have been described as "anachronistic," being simple round-ball muzzleloaders produced in the 1850's and 1860's, at a time when much effort was being devoted to developing breechloaders. I have collected a decent reference library of my own, but just don't find a lot about these guns. Russell, Hanson, and Garavaglia & Worman all mention them, but the only really systematic study of these rifles that I have seen was by the antique dealer,
Damon Mills. If you click that link, it will take you to his website. Scroll about halfway down the page and you'll find his analysis of the J. Henry & Sons Treaty Rifles. He identified three phases of production, based on features observed in a good many of these rifles. I think his research is good, and he ought to publish it.
However, after all that, I'm not convinced that the Cracker Barrel rifle is definitely a J. Henry & Sons "Treaty Rifle." It shares a lot of features with them, but it also has a few minor differences. It would be great if we could get a closer look. I would look for the J. Henry & Sons stamp on the top barrel flat and the lock, and I would check for a US or other letter stamp in the wood back of the triggerguard.
Again, thanks for showing this interesting rifle! The nearest Cracker Barrel in my area is in a community known as "the Berkeley of the South," and I don't think they have any guns displayed. I would be a more frequent customer if they did.
Notchy Bob