The car in the Volkswagen museum is a type 38 - built by Porsche. In the early 1940s - during the war, Volkswagen used it for testing wood Gas and modified the body.
Thats the reason why it survived the war. In the early 1950s, the car was rebuilt back as its design of 1938 - but they used for the restauration components of different years.
In the late 1990s, the car was restaured again by Oliver Herbolzheimer and he tried to give it back the original looks of 1938