Hi Duncan,
wellcome at our forum!
Yes and no! At DC (Daimler-Crysler alias Mercedes Benz) you normally won't have luck. But most seals are still available. The roof window seals and the "normalones" are yardware. The windshield-seal too. You might order them from Reinhard Kainzmaier (just click the Banner at the upper right, if you have communication problems gimme a PN, i am willing to translate).
Getting seals for the sliding-windows (doors) is a big problem, there is a plan of the german 319er-club to get them reproduced - as far as i know. To have one more aspirant would help! Same with the rotating triangle-windows in the front (how would you name them in english, in german: Ausstellfenster?).
Another good adress is
http://karasch-mb.com/. Hard to find on the net, quite expensive, but often knight in shining amor!
Hope this helps for the begining, more questions? Just ask!
AND - we're expecting more details and *PHOTOS* from your car (placed under "Eure Fahrzeuge und die Besitzer"=Your cars and their owners)!!!
sinc
tec