You can purchase a whole assortment of seals, gaskets, rubber and more from a host of aftermarket companies. When I did the rebuild on my 69, I purchased a kit that had vertically everything I needed. Because my Road Runner was stripped of everything and taken down to bare metal then painstakingly brought back to life, we required the complete OEM package, including rubber for doors, trunk and glass, bump stoppers and guides for hood, pad for gas tank, rubber and steel cover plates for engine compartment inspection openings, and much-more more. You will save a lot of money purchasing the complete kits, rather piecing it out. Even if you don’t buy directly from them you’ll find pretty much everything you need from Classics Industry’s Mopar catalog.
It’s not hard for your project to turn into a huge money-pit!! Over the years I’ve dropped a lot of $$$ at Classic Industry, and also at Year One, Summit, Dakota Digital, Rick’s Tanks, Griffin, Retro Sound, Classic Auto Air, Leather Hide Store, Diamond Back, Craigar, Indy Cylinder Heads, EZ FAST 2.0, B&M, ultra cut plush pile carpet from “Stock Carpets”, 200 lbs of Dynamat… I could go on and on, but probably get the picture. After making every attempt to hold myself to a modest budget, the car just seemed to take on its own life… it happens, so be prepared; however, to your original question, I highly recommend getting a Classics Industry’s Mopar Catalog (for reference)!!
What may really surprise you is after trying for over a month to get quality tail light bezels and lens through all the usual distributors, like AMD, JEGS, and Summit, I finally found a manufacturer/distributor in Canada. I’ve also purchased several other products from Canadian companies, including my gas tank vapor canister (considered to be the best canister on the market). Unfortunately, according to the owner, he’ll be shutting the business down in a couple months due to the Trump tariffs. He says basically the entire Country no longer trusts the US!!! I’ve had firsthand countless car-related companies and shops tell the same thing… can’t get parts!!! One high end custom shop (owner) told me last week… and I quote - “all that money and resources you put in that Road Runner - if you were starting from scratch - add 50%). Now I’m afraid to drive it!!!
Take care and good luck. Us Road Runner owners have to stick together!!!