Here is the description on the rifle according to Tyler:
"A heavy target rifle with a .47 caliber octagonal barrel 32 1/2" long by 1 3/8 across the flats, complete with false muzzle and brass bullet starter. This arm is equipped with a double set triggers, lollipop rear sight on the tang and a fully adjustable hooded front sight with three adjusting screws. The lockplate, hammer, upper tand, top barrel flat are profusely engraved as are the brass buttplate, sideplates, upper and lower (3 piercings) butt plate extensions, inlays and trigger guard. The rifle is marked A. LEONARD, 1849 on the lockplate, also A LEONARD, cast steel, 1849 on the top flat of the breech plug and A. LEONARD, cast steel, S.R., VT midway on the top flat of the barrel surrounded by engraving. Another unique feature of this rifle, which is thought to have been Mr. Leonards own, is its twin cheekpieces on either side of the nicely checkered and polished stock. Lastly this highly ornamented rifle is marked on the top left barrel flat: Geo. O. LEONARD, KEENE, NH., CAST STEEL, 1867. This would indicate that George re-rifled his fathers own target rifle 18 years after it was made"
If you go back to my first comment....you will note that I mentioned the cheek rest was unique...you don't see that on Vermont made rifles from this era....and Tyler repeats that in the quote above.
Also....I don't know if you caught that....but this was thought to have been Artemas Leonard's own rifle! Not sure if that is him in the picture...he died in 1859....and you won't likely find another of him....but all in all....the possibility is pretty amazing. Please keep me posted with anything else you may find out.