Yes.
You will need to contact Walther to find out.
1961
http://www.p38forum.com/
Dieter Marschall's book on Walther has sn data in it.
Try asking on the p38forum.com
5000$
Try the P38forum
Military P38s are dated from a 3 letter code, and not a serial number.
Someone at the P38forum.com should be able to help
Someone at the p38forum.com will probably be able to help you.
The Walther P38 with a serial number 6660 was likely made in 1940. The P38 was produced during World War II, and early production years can be identified through their serial numbers. However, for precise dating, additional information such as the manufacturing code and proof marks would be useful.
You will have to find a copy of Dieter Marschall's book.