OWD, you really don't specify, that I can see, what kind of a gun is being restocked. If the original stock is broken or bad for some reason, then a new stock would increase the value.
If the original stock was fine, factory original, the the stock was then replaced, the value of the gun would probably go down.
Very good point. Stocks and barrels are "usually" replaced for a very good reason, that being, the originals are so damaged that it makes the gun useless for either shooting or collecting. Unless the job was done by an incompetent gunsmith, the vast majority of re-stocks/re-barrel jobs I have seen have added value to the gun, as opposed to what it's value/condition was before the restoration.
Unless the gun has a specific historical significance, I have yet to see a gun with terribly pitted or otherwise damaged barrels, and/or a significantly damaged stock, that is worth more than it would be if the appropriate repairs/restoration were made by a competent gunsmith.
