Hi Scott,
Here's what I found out about your bass:
SMB4 Spoiler 4-string bass
body: Solid Koa
neck: 3-piece Maple
scale length: 32 (medium)
fingerboard: Ebony
inlays: Pearloid (plastic) ovals
birthday: March 21, 1983
originally made for: Sam Ash, Paramus NJ
The original owner was from New Jersey and they registered on March 30, 1983.
It was reregistered in 2004 to another person in New Jersey. They commented there were a few finish cracks.
I also found out there's a Series II Exploter bass with the serial number 83-2556. Ooops!