We don't generally restore bikes for resale ourselves, rather, we restore-to-order. The market for vintage lightweights is too thin to restore on speculation. With balloon tire classics, there may be some cases where refinish for resale works out well because the market is larger prices are more established and there were less fewer size and color options.
Buyers are suspicious of refinishes and the damage or modifications it can hide. Also, many collectors or nostalgia buyers are very specific in their desires; quite frustrating when the refinish is not the color the buyer had in mind!
If you are selling, better to keep old bikes in their original state. Some buyers are only interested in original finishes no matter how bad they are. If the buyer is not happy with the finish let him that complete accurate refinishing services are available from CyclArt.