Juergen:
Thanks for your response here. You have said, pretty much what I have thought all along. The front seat that I have came out of a late 37. At first it was thought that it was actually an early 38, but the upholstery is the 37 design.
As for the rear. Snyders claims that they are different. I know that they are in the business, but I tend to believe that the 38 Standard is either, the same, or very close to the 37, but different from the 38 DeLuxe and 39's. The 38 DeLuxe was different and the body was bigger, so it would seem appropriate that the rear seat would be wider. Who knows, but I am leaning more and more towards ordering the new 37 seat from Snyders if I can' find a good original rear seat. Thanks again.