Does anyone know what the N stamp in this Galil serial # means? AALN-2078XXX. N looks added after the original # and has no paint in it. This is a NOS 332 - 7.62mm ARM, 20" bbl dated 4-87, 1-12” twist, bayonet lug on bbl, pinned bipod, Galil style flash suppressor. No mill cuts on receiver and...