The 37 frame split in the middle on the sides to replace the glass and the 39 is offset toward the bottom. The passenger and pickup farmes are the same for each of the three years listed, although the pickups tended to use the painted frame used on the Standard. There was a 37 Deluxe pickup that used the chrome frame, but I am unsure if there was such a thing as a 38 or 39 Deluxe pickup. My 39 had a painted frame.All of the passenger and pickup frames from 37-39 had the same dimensions and are interchangeable as to size. Open cars were not the same from what I remember, but I have never owned one.