Hi Richard,
Here is what I found out about your bass:
88H5110 HMB4 Elan 4-string bass
top: Quilted Maple
body: Rock Maple
neck: Maple and Purpleheart, 32 medium scale
fingerboard: Ebony with pearloid ovals, custom size 1.650 x 2.323
pickups: JZ
controls: a little confusion here*
output: Mono, face mounted
originally made for: Rokkomann, Kobe, Japan
birthday: not recorded, but in October 1988
It looks like it was a custom order. The pickup position is custom, the fingerboard width is custom, and there is a special instruction on the work order to make the neck EXACTLY the same as the fingerboard width at the neck to body joint.
*As for the controls, the work order states it is a 2 volume, 1 filter setup. The wood card says it is a volume, filter, pan, Q setup. The picture looks more like the two volume set up. Let me know for sure so I can ammend to file to not be amiguous.