Tom,
Check out post #5 in this P38 forum link:
http://p38forum.com/forums/showthread.php?t=14732
The post says in part:
"The front grip strap marking makes it easy to identify the gun as one of the Berlin Police Force during the occupation era between 1945 and 1949. It served in the Soviet sector in the inspectorate of Friedrichshain. The mark reads as "S" for Soviet sector, "V" is not a letter, but a roman number "5", followed last by the early Berlin Police ownership-stamp. Berlin had 20 municipality-districts which were equal in size to the police-inspectorates and were numbered with the roman numbers from "I" to "XX".
Below is a photo the S V marking that is referred to in the quoted statement.
Marc