I have 5629287 it is thought to be an original piece right down to the AU recoil plate. It was made in march of 1944. They were using both type3s and flip sights at that time. I would say that the rear sight on yours is original to the weapon. The staking on the front sight is not what would be expected from Winchester, I also would not expect a type 3 band on this gun a type 2 would be correct.