Aluminum hoods on Mustangs and other pony cars started in the 80s and before.
The repainting thing is more and more common on steel and plastic/fiberglas hoods as well - it’s due to the ‘eco-friendly’ paints makers are forced to make, not the substructure the paint is put on.
Supposedly they bead blast the hood, using steel beads, is supposed to be coated with a primer that prevents steel rust from the trace steel left behind. They failed at that quite a bit I have been told. The body shop who fixed it was supposed to use a similar priming agent. It didnt work. Now its only a few months since the last painting. Lets see what happens after 2-3 years.