On mine, a 91 which didn't come with the rails pre-installed, I remove
the metal strip on the outside (3 or 4 screws are all that hold it in
place) when I want to slide the seat out (or in). I have to do that
with my passenger Vanagon too, so it isn't that big a deal to me...yet,
I'd love to have the early set up with the 3 piece metal strip and
inserts. Maybe the next time I go to the junk yard I'll get lucky...