They all had the Custom Shop stamp, naked or not. It was something to keep the Custom Shop - as a marketing tool still fledgling at the time - busy and perhaps it was also down to Wayne Richard Charvel's influence who was supposed to walk on water for Gibson at the time. The Q-80 was his only bass creation for Gibson (by the slightly changed Q-90 he had already left in acrimony), a rather loveless affair given its unaltered Victory body shape, the already then more than a decade ancient Grabber pups and the kind of indiscriminately added trademark Charvel headstock.
But it was also the end of Gibson's maple era that had started some 15 years before. The Q-80 did feature maho as body wood again.