There is a channel as part of the door skin construction which holds a tongue of the weatherseal. The channel is crimped to hold the rubber. Originally there were 12 clips (7390958) per door on the rubber to push into the slot. I only have 5 which I think came off my 1st V4, at least they match the image in the parts book. I tried to glue it in place, using too much and it melted all the paint....
Onno Kempink in the Netherlands sells them: http://www.classicsaabparts.nl/c-458338-2/carrosserie/ The thing is called 'raamafnemer' in Dutch, 'links' is 'left' and 'rechts' is 'right'. 'Raamsnor' is the inner felt and 'raamsnor klip' is the clip for the felt. No clips for the rubber on his site, but he might have them as well.
I think it's a horrible construction as the clips tend to scratch the glass, the metal under the rubber rusts as hell and I've never been able to properly retrofit one of these rubber b.astards. Also tried the ones Jack Ashcraft sells, but they're a waste of money as they won't fit and they're 5 times more expensive than the exact same profile the rubber man around the corner sells.
1970 96V4 "The Devil's Own V4" 1977 95V4 van conversion project 1988 900i 8V