Never replace any part(s) that you will have to alter the instrument by drilling hole(s) or routing out the body in any way,period.Never refinish or repaint any portion of the guitar.any electrical parts that must be replaced due to a malfunction should be done with the very least amount of work necessary.Any electrical part that you want to replace to change the tone should be kept to a minimum and if possible replace the entire pick assembly in strat style guitars ,so that the only solder broken is at the input jack,save all parts that are replaced ,in the guitars case,make a note stating ,why, what  and where all changes were made,including the date of such changes,and save the receipt if done professionally at a shop.Keep all these items in the guitars case also. It is unwise for pricing purposes to do anything to a vintage guitar ,especially anything that can not be reversed,even a fret job detracts from the price on a future resale of items. If you are a player and have a vintage guitar I advise all work done and documented at a repair shop that is well known and seen in high regards within the guitar community. again keep a register af all work done and when and why and by whom,and keep all the original parts,you will be glad you did if you ever have to sell your vintage guitar!Greg at www.gregsguitars.net  have a great day.