72 Dodge Dart Swinger

Nice find, I believe the factory color is white.
Nobody would go thru the trouble of painting it under the hood, then letting it get that greasy.
I've found white, cream and even gold in multiple places on the quarter panels. I've wandered if the fender tag has been replaced but I dont know. The door panel metal is painted black where it is usually body color and I have seen what appears to be black over spray in a few hidden corners.

But i agree that it sounds unlikely. I don't see any hard proof of a vinyl top either. However if somebody dedicated enough got rid of the top, did it right, they may have painted it correctly.

The puzzles of the old cars.