I'm surprised anything of those kits exists in any form. Revell was always borderline profitable, especially back then. Had they made a ton of money in any one or two years, they'd probably have scrapped those tools to take them off of their inventory.
They never really had any intention of using them again. Even during a down period in the mid-Seventies, they dragged out the early multiple piece body car kits like the Porsche Speedster, '57 Ranchero, and early Corvette, but apparently no thought was given to bringing back any of the Mopars...
--Mark