I used the grey felt they sell in the window & door seal isle at the hardware store.
Cut to fit and cut the little holes for the flap retainer to press thru and snap it together like VW did originally.
I'm just not trusting the glue on the truck cap foam to stay stuck.

It's in a spool as felt wetherstrip and you'll get 19'f too much out of a 20'f roll. But it's cheap and handy for other home & auto projects.

While you have the heater out, I'd suggest adding the �" square steel mesh "Hardware cloth" between the heater and the intake from outside to keep mice out of the core.. not much worse than mouse pee on a hot heatercore.

Best luck
Dan in NY

It looks to me like the heater flaps are constructed with a metal base
> =
into
> which a plastic rectangle was pressed, the foam seal being held =
between the
> plastic and the metal (don't know if the foam was stuck to the plastic
> =
or
> just held in place by it).  Should I
>=20
> (a) leave the plastic there, and stick my foam to the plastic?
>=20
> (b) remove the plastic and stick my foam to the metal?
>=20
> (c) remove the plastic, put my foam in, stick the plastic back on?