Look s like a 1942 Mauser-produced "Model PO-8" standard military issue "Luger".Although the Walther designed P-38 semi automatic service pistol officially replaced the Luger (German standard military service sidearm adopted in 1908) - the P-08 pistol did remain in manufacture thru the end of WW2.
Mauser, Spreewerke and Walther all produced the more modern design P-38 pistols,but the chief producer of the post-1938 Luger was the Mauser factory. The Luger was much more costly to produce than the P-38, and that was one of the major reasons why it was replaced. Most of the parts on a P-38 are stamped, while the Luger design required a great deal of milling and fitting.
Your pistol looks to have the original finish, and looks like it is parts-matching. Another possible 'plus' would be if the magazine would happen to match to serial number of the pistol. I cannot give you an intelligent guess on the value because I've been away from that sort of thing for many years. Someone with more current market experience will be along shortly.