any local engraver can add new numbers to your trunnion, bolt and carrier. specialized markings such as arsenal stamps or inspection/acceptance stamps will have to go out to a pro.

since you are using an american receiver, your s/n will be located on it.

sarco was advertising some e.g. kits a while back. i'm pretty sure they were stamped akm type parts sets. i do not know if they still have any.