Hi Phil,
Here's what I found in the file:
BUILD RECORD
top: Flame Maple
accent: Walnut pinstripe
body: Maple
through body neck: 3-piece Maple, 34 long scale
fingerboard: Ebony
pickups: 2 Alembic MXY
controls: Essence (volume, pan, filter, mono output)
originally made for: Bass Centre, Los Angeles
birthday: December 20, 1991
It was returned to us in 1993 by an owner that lived in California. His note to us states: midrange/slap ability. Needs new pickups? We show return shipping, a week later, but I'm sorry that there's no detail of modifications.
If you post a picture of the inside of the electronics cavity, I can let you know if the electronics were made by us, or if any of the original circuit is intact.
As an all-Maple neck-through bass, the tone should be clean, clear, and quite bright. Even without amplification, the bass will not naturally produce much midrange due to construction (neck-through) and material (all Maple).