The pickups should be identical. You can measure the restistance and see if they are a close match. Usually the neck pickup is farther away from the strings. You might want to increase the gain with the trimpot on the back.
Today Bill found the work order for 394, but it did not match the pictures of your bass. It was for 83-2769, an Exploiter Series II with no humx in Quilted Maple. We'll keep looking for clues!