I know where you're going with this, as the pickup sizes suggest AXY/Fatboys, and the holes for the pots REALLY suggest an ALEMBIC style layout.
It's just amazing to me that while in the 80s the Japanese made zillions of Fenderish clones, their hearts and minds were REALLY struck by ALEMBIC.
The ARIA SBs, the BB Yamahas, the Musician Ibanez basses, the Daion XX, the Westburys, all are heavily influenced by the ALEMBIC design.
I've always thought of the SBs, BBs, and to a lesser degree the Musicians, are really overlooked gems in the vintage market. Like most Japanese basses, they are only let down by their pickups/circuits. They went for an open sound, but missed the meat that ALEMBIC pickups added to that open sound. (Just listen to a new Nathan East or John Pattitucci Yamaha: Where's the beef?)
I don't know if a vintage SB is worth spending the money for a complete electronic retrofit, as I always buy a bass low enough up front where I can always easily get my money back out of it on the day I find something else I can't live without. But if it suits your heart, GO for it!
Incidentally, Bartollini used to offer
replacement pickups for SBs, but then it would just sound like Bartollinis . . .
J o e y