http://www.motoradusa.com/aboutus/index.htmlThe Locking Caps from Jim's are made by Motorad and are repackaged and come in a small plastic ziplock bag.
Search the motoradusa.com website (Catalog) for local dealers and your car.
I saw the same gascap today in the Hardware Store for $18.99, it is listed as MGC-771 for a 1970 Challenger 440 with Flip Fuel Cap.
Jim's number is GC-771 @ $54.95! Note the similar number and price difference.
I also searched (on Motoradusa.com) for a 1969 Charger gascap, it's listed, and probably lots more gascaps there for other Mopar models.
Thought I would pass this on.