There is 2 possable manufactures of your P-38 war time pistol.If your P-38 has a byf code then it was made by Mauser Werke,Obendorf am Necker in March/april 1944.If your P-38 has a cyq code then it was produced by Spreewerke of spandau berlin in june 1944.Both of these manufactures had serial numbers with a R suffix.