Let me salvage what can be salvaged then. The bass you described and the pictures I've seen showed a Westone Thunder 2 bass, which was an eighties model made by the Matsumoku factory which also gave us Aria Pro 2, Washburn, Vantage and Electra.
The Thunder range featured solid Sen (A Japanese variety of Ash) bodies with DiMarzio licenced pickups. One P bass pickup on the Thunder 1 and the Thunder 1A (which had an active two band EQ) and two of those Units on the Thunder 2. The Thunder 2 also differed from the Thunder1 and Thunder 1A by having a neck through body construction.
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A Westone Thunder 1A
And the back of a Thunder 1 series bass showing the Bolt on neck.
The thunder 3 guitar series, showing the Alembic style attributes.
The thunder series guitars and basses were meant for beginners, offerring a well made instrument which included a case. The range lasted until the Westone brand went belly up in the late eighties and subsiquently became branded Alvarez but the Thunder didn't live to see the transition. Westone instruments still offer plenty Bang for the buck and usually can be picked up for very little money.
Having said that, I doubt that the bass you saw Louis Johnson playing was a Westone. I suspect it was a BC Rich Eagle. Seeing how he used those as well as using his musicman basses.