They got scrapped after there was no longer any demand for the parts. Every attempt was made by the mfr to supply service parts after the model year run but after several years they would tell the Parts Division to give them an "all time buy" after which the dies could be disposed of. In some cases the panels were carried over for two or three years thus allowing the dies to remain set up in the mfr's plant but ultimately the same thing happened.
Chevy (and probably the rest of GM) used the Jam Handy Organization in Detroit to produce all their propaganda films. It was all highly professional. Ford had its own in-house motion picture department which recorded almost every aspect of Ford's production beginning in the Model T days.
The Jalopy Journal
