Hi, you are correct in describing the procedure for installing a window with
the rubber into the window opening.  What we have been referring to is some
of the later vans had what thought to be a deluxe window molding.  The
molding had a grove in the outside face into which a clear PVC (which had a
chrome like strip inside) was pressed into.  The PVC will become brittle,
turn brown and shrink over a period of time.  This is due probably exposure
to UV light, heat, and ozone.  Some other makes of vehicles use window
moldings in which this type of finisher also does a double duty of locking
the molding tighter around the glass.  I don't think this is an issue with
the Vanagon and we could get by just removing the PVC strip.  For those who
want greater peace of mind I was suggesting the 1/8" tubing idea.
Cheers,
Kevin Dawson
87'  Wolfie