Howdy!
You should pop over to the P38 forum
http://www.p38forum.com/ and post these photos.
The folks over there are friendly and knowledgeable and can tell you
everything about your pistol!
What you have there is an AC42 P38 9mm pistol. The "AC" was the code for Walther. (P38's were manufactured by Walther, Mauser, and Spreewerk.) The "42" is the year of manufacture.