Is it just me, or if you have a used bass and it is missing a serial number for any reason, the resale value is brought way down unless there is some other way to authenticate the bass. Examples I see are: 1) a serial number on a metal plate is removed, presumably because someone didn't like how it looked or feel 2) the bass is refinished in a non-standard way covering or destroying the serial number. In the latter case, I would think the value should be very low because the ability to confirm authenticity is greatly reduced and it doesn't even look normal, but the postings try to make it like no big deal. If you plan to modify an instrument that you may later sell, keep some sort of documentation. For example, a certificate of authenticity, sales receipt, picture before and after modification, receipt from the luthier modifying the instrument including the type of instrument before and what was done. It just seems unlikely you would have no proof if it is a legitimate instrument. Especially with the number of counterfeits around now.