Hey Paul -
Another note on the B Series basses is that the necks were HUGE - big, fat & clubby.
The store I worked at in the early 80's was one of the top Ricky dealers in the country at the time. When the B Series was introduced ('84 or '85,) we sponsored a booth at Beatlefest in L.A. that year. Charlie Malyska (the So. Cal. Rick rep at the time) and I brought down all 5 models (including a Fireglo & Mapleglo bass) to display at the show and take orders (we sold 1 guitar.)
I was down at the offices/showroom several times during those years, and all of the B model basses I saw had the same fat necks.
That could well be, but they may have been 4001V63 models by then. That model started in 1984. The tell tale differences include the "reissue Horseshoe" pickup, ½" spacing on the Toaster-top pickup (to the fingerboard), and the acrylic back-painted long truss-rod cover. The 4001SB and 4003SB are pretty rare (those that can be identified as such). Don't know enough about the guitars, but I think 1984 also saw the changeover from the abortive B models to the newer, more accurate V models.