Yes, I understand that 14593 is some kind of serial number, but does it stand for something special, like the 14593:rd Signature Standard Bass that You are making or something like that? That the cavity is for the upper pickup I also understand, but is the serial number in some way tied to the pickup? If that's the case the other cavity should have a number as well.
About flying basses! This one has some more flying to do when it's ready, right?
Erik