This rifle is a real gem. Much of what I'm reading by those who really know these southern rifles strongly suggest a restock, though the person that did so looks to have added a few 'personal' touches. I think the intentional shadow line on the cheek piece is very distinctive. The rear sight, as noted, is extremely well made, exquisite actually. The filing on the Soddy style butt plate return, which are usually plain/smooth (I think) and the matching filed ram rod pipe(s) were I think added accents. These features may help establish the builder of this piece.
The swamped barrel is a forged piece of art in and of itself. The .58 caliber bore, as Cades Coves Fiddler pointed out would have permitted it to shoot ammo from military reserves. The shortening of the barrel was obviously deliberate, though I have to submit that it is much more 'horse' friendly at that length and makes you wonder if its owner thought it a more useful length for a rifle heading into the west after the war.
Ken Guy had written about these iron mounted SMR rifles built using locks from Harpers Ferry muskets and using the British Enfield lock on this rifle, replacing the original, makes perfect sense and is actually a very close fit. I would think a military grade heavy main spring and a lighter sporting hammer, would make for a very quick lock time.
Just a super, super piece to study and discuss.
One thing is certain and that was I was really, really far off in my engraved 'signature' guesses. I think Cades Cove Fiddler nailed it with 'Garland'. The engraved 1883 date is a bonus, regardless of who, or what, it represents.
Q. Does the barrel evidence any wear pattern, from the ram rod, along the bottom flat? Just curious...
Thanks for all the great photos and details.