I recently acquired a complete trigger group for a model 12 shotgun. Looks like NOS MILSPEC TO ME, parkerized and not a mark on it from use. From what I can learn only trench guns were parked during WW2 and riot guns were blued. Was wondering if I should just use it for spare parts or it may be desirable for someone building or repairing a trench gun? Also got an original rear sling swivel for a trench/ riot gun in the small box of parts. Sling swivel looks identical to those inlet into the butt of a 64 or 71 Winchester deluxe. Will post pics if anyone can identify it as original.