How can I tell if my car has the original paint?

Long story short I have a 72 dodge demon and was under the assumption it had the original paintjob. From what I understand about the paint jobs back then it was a single stage paint with no clear coat.

I had it detailed the other day and wanted to let him know to take it easy with the buffer since there wasnt any clear on it. Got it back from him and he did a great job but he mentioned he thought it was a repaint and that it had a clear coat on it. I bought the car for dirt cheap so I still got a deal on it regardless. I know very little about paint/bodywork so I was hoping there would be some tell-tale signs of a new paintjob or if it has a clear coat.