I tried to remove them and paint them...that's a mistake.  If you remove
the strips, they will be cracked and distorted to the point of disposal.  I
did purchase the straight black window rubber (no trim) from one of the
list vendors (Bus Depot?).  I was in the painting process and replacing the
windshield, so new trim front and rear made sense.  One thing I recall well
is the hellish time the glass installers had putting the rear window in.
At one point there were three guys swearing over it.  The new rear trim was
very very tight.

We are in the winter salt zone here, but the van is not used in winter.  It
was amazing how much rust, including a few perforations, was found sitting
in the window frames.  On the front windshield, I ground/blasted all the
rust away, then laid one six ounce layer of fibreglass along the bottom of
the frame, using west system epoxy (with microspheres) to bond and seal
it.  The entire frame then got epoxy primer with the rest of the van, and
then top coat.  Needless to say, no problems have shown up in the last four
years.

I guess the point of this is that if you are replacing trim, prepare for
some body work.  I wish I would have done the side glass too.  There were
no problems four years ago but I've just noticed a small bubble at the base
of one of the rear windows.