Posted: / By: By: The letter went up one character each time the serial number once more started at 1. There is no correlation between the models and their respective serial numbers (i.e. At the beginning of a new year, both the serial numbers and suffix letters again started over. Hoffschmidt's 'Know Your Walther PP & PPK' or Gene Gangarosa's 'The Walther Handgun Story: A Collector's and Shooter's Guide.' There is no suffix to the serial number. PPK production started shortly after that (maybe late 31 or '32) and used the same serial number range as the PP model. The first variation is in Eagle 3 5 9, now 3 5 9 was the inspector approved for the Walther factory. Has some holster wear on slide, but other than that, pretty clean with original bluing. 3-digit number inside slide (scratched with a needle) Acceptance stamp: Back grip strap. This matching example falls into the end of the noted second serial number range. Please contact Walther Arms via phone (479) 242-8500 or email us using the Contact Us form if your PPK or PPK/S serial number is within the range of recalled guns.