* A P.35(b), or 640(b) as the Germans called it, will be in 9mmP.
* This pistol was made by DWM-Werks Luttich (FN-Herstel, Leige)plant. The FN plant was seized by the Germans on 5/20/40. DWM - Karsrule "acquired" the FN plant & provided oversight/management of production shortly thereafter. DWM was a subsidiary of the famous Mauser Werks in WWII.
* Few records survived WWII. FN disavows pistol production by their company during this period @ Liege; but, acknowledges 80,600 HP's were completed in 1942 by the Germans as stated by Monsieur Leloux to a CIOS team per R. Blake Stevens in his book The Browning High Power Pistol. My stab @ reconcilling production quantities & dates given by Whittington, Still, Stevens, & A. Vanderlinden suggests your 1312xx was produced in the 1st Quarter of 1942. Possibly early Feb., 1942, about 10 days before my example.
* The WaA140 is not a contractor; but, rather the Waffenamt inspection team assigned to the Leige plant. They reviewed/accepted production on behalf of the German Armed Forces. In 1942, this group was headed by Oberleutnant Zorn.
* Do you have a holster & original mags with this bringback? Pictures would be appreciated if you can negotiate the pixel pixies.
* Trust this helps.