If the S12 has not been imported without a stock or every had a stock on it so it can be labeled an AOW if not it has to be labeled a SBS. If it's a virgin receiver it can be labelled an AOW. I'd love to have an AOW, but I only know CGW making them now. Some states will allow AOW's not SBS so it be nice to have another vender doing AOW's. Nice looking conversion.