I did A LOT of digging in to this a year or two ago and the short answer is yer SOL.
The thing that I ended doing was going back to my secret stash boneyard that has a bunch of mid / late 70 Dodges and grabbing every upper clip I could get my hands on. The good news here is that the clips are pretty sturdy and can be re-used. Yeah, I know how many of these things ya find in boneyards these days.
The biggest after market clip maker is a company named Auveco and back in the 70s they may have been the OEM supplier. I've found PN crosses between ChryCo and Auveco but all the stuff is disco and history.
https://www.auveco.com/moulding-clips-retainers
www.car-pak.com is another huge supplier but thier web site sucks. You have to download the pdf catalog then dig through it to find out its no help.
Mr. G's Fasteners caries a lot of stuff and some of it is listed by the ChryCo number but they don't have any thing for the upper moulding.
www.mrgusa.com
AutoFastCo listed the Auveco replacement on their site. When I went to order it they said disco and history and updated their page.
https://www.autofastco.net/Dodge-Chrysler.html
The ugly option is drill holes in your fresh paint and use something generic like this:
http://www.hillcofasteners.com/prod/Universal-Moulding-Clip-with-1024x34-Stud-516-Wide-x-34-Long-Plate-Replaces-Chrysler-1624705-6010093__AV02744.aspx
Another ugly option is randomly buy what ya can find that has the same advertised dimensions and keep trying until you find something that fits. One example that comes to mind is the clips for the vinyl top moulding on late 70s Mopars. If ya put it next to the truck clip, ya can barely tell them apart but the car clip doesn't work - it's a hair too narrow and doesn't grab the moulding.
A thing that's been done with the clips for the wider lower moulding: take the best used one you have and find somebody with a 3D printer and have them make some. It will take some trial and error but it could work.