Try the P38 forum.
1961
Try asking on the p38forum.com
Ruger never made a model called the P38.
Yes.
9mm luger.
Try the P38forum
You will need to contact Walther to find out.
Someone at the P38forum.com should be able to help
Someone at the p38forum.com will probably be able to help you.
P38
Dieter Marschall's book on Walther has sn data in it.
Someone at P38forum.com might be able to assist you.