U.S. Model 1861 pattern musket (AL2479)

U.S. Model 1861 pattern musket with no maker markings. This gun has absolutely no maker markings. The only markings on this gun is the lock is dated 1864 and there is a 3 on the left hand side of the barrel near the breach. No markings are anywhere else, no barrel proofs, no US on the butt plate and no cartouche. We are not sure exactly what this gun is as we can not find a reference to a gun like this. Condition is very fine, no pitting and nice wood!