I've just pulled most of the rubber off my parts car, some bits I'd say are possible, straight sections that could be extruded and cut to length, but my guess is no on any of the curved molded pieces like the big seal around the door.
Here is a link to the Pelican catalog page on rubber body stuff.
http://www.pelicanparts.com/catalog/shopcart/928M/POR_928M_BDYsl1_pg1.htm
Pricey items are;
928-537-323-03-OEM
Door Weatherstrip Window Channel Seal, Left, 928 Brand: Genuine Porsche $185.25
928-537-321-03-OEM
Door Weatherstrip Outer Window Seal, Left, 928 Brand: Genuine Porsche $170.75
928-537-322-03-OEM
Door Weatherstrip Inner Window Seal, Left, 928 Brand: Genuine Porsche $162.25
928-512-129-02-M100
Rear Hatch Seal, 928 (1978-86) Brand: Genuine Porsche $92.75
928-512-129-04-OEM
Rear Hatch Seal, 928 (1987-95) Brand: Genuine Porsche $211.75
928-543-038-04-OEM
Quarter Glass Seal, No Spoiler, Right Brand: Genuine Porsche $227.00
928-537-346-05-M260
Door Seal, Right, (1978-95) Brand: OEM $143.75
Prices vary from difference sources, but these are typical. Maybe we should just be glad the parts aren't NLA.