66 valiant rear glass seal needed

Yes and they still carry bulk weatherstrip. What you have to do is cut yours, look at the end profile, go on their page and match it up best you can.
If anyone still has theirs I'd like to see a profile picture of it mine is long gone , thew it away never thinking it was such a unicorn. I was told by a glass guy that a 65 rear window gasket can be cut and glue to successfully fit as the 65 was bigger and ightly rounder.