There is a video at Youtube from a Midnight Special show in 1973 where Steely Dan performs "Reelin' in the Years".
In this video, Walter is playing a bass with 2 Jazz pickups and a Precison pickup in the middle.

Is anyone familiar with this instrument (history of, the ompany that made it, was this something Walter designed and had someone build for him, etc.)?

Any info would be appreciated.

This pre-dates Fender's Stu Hamm Urge bass by about 20 years and I was just curious about it.