I'm not knocking the bass; hell, I had put a bid in on it. However, trying to figure out what things are is, to me, interesting because it invites closer study on things I wouldn't normally scrutinize. We do it in the antique motorcycle world all the time. I think the bass is pretty sweet and damn nice looking.
Thinking about it, if the neck IS from a BaCH, another bass or luthier-made, perhaps the inclusion of the serial number was simply to indicate what the serial number of the original was. This one is just a number: did they originally say "Made in USA" in addition to the number like more modern Gibsons?