If you purchase an instrument, with the intention to sell it one day, then do nothing to it that changes the stock assembly. This doe not mean that you can do upgrades; you have to keep all the original parts back on before you sell it. If your a fanboy who loves particular brand and never plan to sell the instrument of your fan love, then do anything you want to it, including covering it with decals. If you plan on buying an instrument on the used market, know your product: all the parts, peculiar features, serial numbers etc. If you choose not to do this, then you get what you deserve. If you attempt to sell an instrument that has modifications that you did not disclose, then don't complain about the beatdown that is coming your way. Finally, if you have to ask whether it is okay to do anything in anyway that changes the original design of an instrument, and still pass it off as the original instrument, you already know the answer. But in all likelihood, you will find some shill who will soon be parted from his money.