RE: Swivel Seats
Don't forget that there are a lot of earlier (pre '86?) Vanagons and Vanagon
Westfalias out there that were in an "L" series trim package, not the "GL"
we see on virtually all later model Westies.  Ed Anderson built a lot of
Adventurewagens on the "L" series bodies.  And IIRC the swivel seat was an
option on early models.  What's the difference? Most obvious, based on what
I've seen, is the "L" series has no tach and the analog clock instead,
rubber floor mats instead of carpeting. I'm sure there are other differences
in the trim but those two stand out.  And I'm guessing the swivel seats are
part of those differences.