I found a seller on Ebay selling 67-69 Dart ones. If you have one to follow they are easy to make out of heavy mill ( 4-6mill) plastic sheeting
If you don't have one, get a photo of one installed and that will guide you on what gets covered and what doesn't. don't forget the tail that tucks into the slot in the lower part of the door / quarter and some gaffers tape to hold it in place
Door Window Moisture Barrier Water Plastic Sheet Mopar They have 66 barracuda. Might have others just not on their site
I believe they are referred to as Dust Shields or at least another search term to look for.
and the rope calking can by had at the hardware store or amazon
https://www.lowes.com/pd/Frost-King-1-fl-oz-Gray-Paintable-Solvent-Caulk/3411754