The side plate has no notch and it is too big to put two screws into the lock. It is probably from a 1st model bess. Only one screw was put in the lock and a wood screw was in the front of the side plate. So i believe this was put together mainly from a 1756 light carbine using the barrel, lock, trigger guard , butt plate, ramrod guides ...and side plate from a 1st model brown bess.