72 Dart Swinger Value

You paid what you felt comfortable with. No reason to feel bad if what you saw was worth that.
But... Perception makes the deal. In my experience primer is a warning sign. I can see what's under paint in most cases. Primer hides a lot. SO cheap, orange peely, and shiney, all one color will always "feel better" to me than perfect steel dressed in only primer. Plus - primer is porous. So water is reaching the metal, even if in small amounts. So first thing I'm doing is stripping it down to metal and starting fresh.