Every once in a while a beautiful "original" classic shows up with so perfect paint that it appears to be a repaint, but isn't, and if it is a quality bike, then it can command a pretty penny.
Then there are those bikes like my old Colnago Super. It may well be a classic. Not that there aren't a lot of Colnago Supers out there, but I'm pretty sure mine is a very early production model. But, it has been ridden hard for years and years, and it shows.



As-is, my old Colnago is probably hardly worth the value of its mismatched wheelset. A fresh coat of paint, and tracking down its original parts (or replacing the groupset), and it could easily fetch over $1K.
For now, I'm content with the wolf in sheep's clothing look.
Then there is everything in between.
It is easy to both look at a nice old classic on the road, and pick out every speck of rust and complain about the horrendous condition.
So, one could certainly go either way with a quality restoration or a patina look, each with different effects.
I did see an old Cannondale M500 with the long dropouts at the Co-op the other day. Clearly a repaint, but it really looked nicely done. It will never regain its former glory days, but nice nonetheless.