I wonder if the different style of seats relates to which of the four manufacturers built this vehicle as well as to which of the seven production runs it was built in ? I'm thinking bucket seats in 1936 , and ending up with simpler round seats by end of production in June 1943 . The Germans did make things simpler and cruder in detail as the war dragged on , ex MG 42 . Lots of stamped and spot welded sheet metal , with plastic / bakelite stock and pistol grip . Any thoughts ?