Thought this bass looked familiar; it was discussed on Talkbass earlier this year, post #4735 onwards:
Nice! And you still have all the mute hardware as well, should you choose to freshen them up and use them! Nice mojo. Beautiful neck. "If This Bass...
www.talkbass.com
Similar questions being asked about the decal. It would be the correct decal if it had the 'Ernie Ball' bit above 'Music Man'. This might be a wild guess but could it be possible a previous owner removed that bit? Maybe get the microscope out for evidence...
Preamp looks like the one on my February 1987 StingRay. The date code on the volume pot (under the black) on mine is 8341. Can't tell for certain from your pic but it looks like so is yours.
As for a possible neck swap... That's certainly a possibility. I once had a 1989 Blueburst StingRay with a rosewood board that according to the database should have been maple. I managed to track down the original owner who assured me it already had a rosewood board when he bought it from new. Someone from EBMM Customer Service told me it wasn't uncommon in those days for a dealer or distributor to swap necks for a customer.
Also, the database back then wasn't always entirely accurate apparently. Looking at the finish that has transferred form the neck pocket onto the neck heel, it seems to match and I can't see traces of another finish/colour. (Well, if there was a neck swap it could have come from another Teal bass, of course.)
Interestingly the bass has a clear guard on the Talkbass photos. Seeing it has the typical cracks around the screw holes - the original clear guards were very thin - I think there's a good chance this was the original guard. Did it come with the bass when you bought it?