I would say, being a Navy arms, and given the scope rail w/missing mount & scope that it is probably either an incomplete Sharpshooter or PU Sniper. Takes a Type-89 scope mount and I think it also came with a barrel clamp mounted bi-pod.
Also, just an FYI, the bayonet is on upside-down. The single protrusion on the spike goes up when folded so it fits into the notch on the lower stock ferrule.