Help me understand what’s going on.

So this is a little interesting. This truck I bought is the classic Chevy gold color doorjames and all. However when I took the plastic siding off the truck it was shinny black underneath all of them both driver and passenger including the bed. Where the paint is chipping up on the truck it’s also black underneath. Do you think it’s possible someone just sprayed single coat over the trucks black paint? There’s no signs of primer or sanding on the black surface anywhere. So moving forward how should I go about fixing this if I wanted to repaint the truck?