1972 Demon bucket seat foam replacement?

I am not an upholstery expert, and someone else may have a better answer, but I recently read an article about upholstery replacement on a 1972 Scamp in the September 2019 issue of Mopar Muscle, and they said the foam is not replaceable because it is molded to the frame. I wonder if your 1972 Demon is the same, and that might explain why the replacement seat foam only applies to 1970 to 1971 vehicles.