I'm confused by a front window seal that maybe should go back into my '70. The window has a front metal track with small Derlin rollers, but it looks like there there should be a rubber seal that attaches to the track to prevent water entry. I know the front triangle window has a (almost) water tight seal, but it is stationery. My '73 has a front window seal that sets into the track, but no Derlin roller set up. What's the deal ?
is there a conversion seal that works on the early models 914'ers, or am I stuck with a surface that will constantly drip into the bottom of my door?

If your glass has the rollers you can't use the fuzzy as it goes where the rollers are. The late mechanism has no rollers in the track, so the fuzzy helps guide it in the track.
You could convert the window over to the late, but it also requires longer horizontal aluminum tracks as the end caps are different. The late are shorter. As long as the window mechanisms work, no real need to change out, unless the lack of fuzzy bothers you.

"unless the lack of fuzzy bothers you."
Quote of the week!