That Mecum sale stings just reading about it. $6,500 for a '69 Chevelle is the kind of deal guys still brag about at car shows decades later, so yeah, I feel for you. Your uncle gave you the rule that made sense when he learned it, back when a repaint usually meant someone was hiding rust or a wreck under fresh paint. The market flipped on him though, and now a decent paint job costs more than that whole car did. Hard to be mad at the guy for looking out for you, even if the advice cost you twenty grand in the end.
Waited 20 plus years for a car to jump 21 grand? That hurts just to read. Look, your uncle wasn't totally wrong back then, repaints used to hide bondo and rust all the time and guys got burned. But the hobby changed. A good paint job today can run 10 grand by itself, so nobody cares if it's original paint unless it's some rare numbers matching car. Passing on a solid Chevelle at 6,500 because of a repaint was a mistake, plain and simple. The old rules don't hold up when even rough project cars go for five figures now.