As @dmccombe7 has said it could have been ordered new with a multitude of pups and preamps (if I'm honest, less so the pre). In the 80's, especially pre 88-89, Warwick would take modifications from their distributors and tweak basses to suit customer orders. This was pre Custom Shop and literally a person in the factory would have picked up what you wanted. Around 86-87 I was going to order a Streamer but I liked the Jazz pups that I'd seen in an advert for the new 'Stage II' bass, the local distrubutor said they could get me a Stage I bass (visible neck) with the SSII pups... and I could have the Yin/Yan inlays at NO extra cost. They really wanted to have a share of the market! Warwick offered their first basses with EMG, Bartolini, Seymour Duncan and even Alembic pups (and I bet I've missed a couple!
Saying all of that, owners sometimes buy an instrument and make mods on day 1 of owning, so there's no guarantee that didn't happen.
Pics would help.