The regulator in the rear glass has something I have found to best describe as a sliding pivot, that snaps onto a ball head and slides in a track. this particular track allows the window to roll up and down correctly, putting tension against the glass so it doesnt drag against the body (I think, its been a few months since I looked at it). Does anyone have a clue, besides a junkyard, where I could find these, ones broke as seen, and the other is gone. Id like to roll down the rear windows on my hardtop. Been all over random mopar trim and interior parts catalogs and jc whitney, etc. Nothing so far.
BTW, welcome to the Dock! I don't have an answer for you and I suspect there are others here with more experience on window parts, but I just wanted to check that you are aware of a company called Restoration Specialties. They can help with a lot of clips and hardware, plus more in the soft-goods area. Don't necessarily rely on their catalog; send them photos and samples and they might be able to help anyhow.
Do you have an factory parts book? If not, check out www.allpar.com as they have a number available for download in their "Technical Resources" section. If you had a part number for this piece it might be helpful???