Please find attached a copy of the Manufacturing Instructions for the RK 1957. The piece could well be a Deumer. It is most certainly not a Steinhauer & L?ck variant. I would sugest this RK was manufactured in the '60's or '70's. Regards Paul H. Attachment source: Bowen, V.E. The Prussian and German Iron Cross - page 38. Privately Published. Sorry, the fille attachment was too large. I'll try again later.