Dieter Marschall's book will get you in the ball park.
No such sn used by Walther.
@1944
70-85
2 number date should be stamped on barrel at the ejection port.
You will need to contact Walther
Dieter Marschalls book should have the answer.
Payment Plan Start Date
You will have to contact Walther to find out.
@ late 70's
You will need to contact Walther.
Possibly late 30s