US patent #50,432 was issued to Westley Richards of Birmingham Eng Oct 10, 1865. It covered the ordinary Doll's Head, though not so called in the patent, with a longitudinal sliding locking bolt engaging the Doll's Head from the rear.
As stated previously Lefever patented the square shoulders, he made no claim as to have patented the Doll's Head itself, No more than Samuel Colt claimed to have patented "The Revolver", he only Claimed to have improved it, which he did.
Don't know if this gun may have done double duty as a target rifle or not. Many Black Powder match shooters of the day breech loaded a charged cartridge case & muzzle loaded the bullet. Some breech seated the bullet & then loaded the charged case behind it. They often fired an entire match, using only one case. It was reprimed & charged with powder for each shot. They felt this gave them more uniformity than using a different case for each shot.