Military P38s are dated from a 3 letter code, and not a serial number.
5000$
You will need to contact Walther to find out.
1961
Yes.
http://www.p38forum.com/
Try posting at p38forum.com
Dieter Marschall's book on Walther has sn data in it.
Try asking on the p38forum.com
100-1000 USD or so
Try the P38forum
Someone at the p38forum.com will probably be able to help you.
Someone at the P38forum.com should be able to help