Hi,
The barrel is a textbook example of a VoPo replacement. Note the rough texture of the barrel crown area. They're struck on the bottom with a single crown/N, no pistol serial number or diameter, etc... Depending on who imported them the caliber may be struck somewhere on the barrel.
These are very excellent shooters, especially the late Mausers like this one. Usually some small springs are a bit tired and may need replacement, but nothing big is usually wrong with them.
Beware of VoPo's with mismatched frame/receive combo's. P08's don't really like to have their major parts swapped, especially those from different makers. I must admit that althoug a bit ratty my WW1/WW2/VoPo frankenluger shoots quite well, but repeating is getting a bit dodgy. It's a combination of a DWM frame and toggle with a 1936 dated Mauser receiver and a VoPo barrel.
This is an image taken from a 1961 Eastern-German VoPo instruction book:
(Ron: I think the overstamp is an 'X' in a circle. Probably done to remove the serialnumber letter from the registered serialnumber).