The appearance of the bass is that of a Series I with Series II neck lamiantion pattern. You are correct that the top and back woods are Zebrawood (nice flatsawn at that). Have you had this bass a long time?
To try and research the serial number, look for a handwritten number in these locations:
1. under one of the pickups
2. one or more of the potentiometers
3. on the preamp circuit card (the side not visible in the photo)
Do you have the powersupply? Maybe add a photo of it as well as its serial number. It might help.
Other things I noticed from the photo:
1. The pickup connector on the replaced pickup looks awkward.
2. It appears that the neck pickup may be plugged into the humcanceller pickup position on the preamp card. If this is true, I expect lots of noise. Confirm humcanceller (center) pickup is plugged into the center connector. Then perform a
humcancelling procedure to eliminate the low frequency noise.
3. One of the nuts on the intonation screws looks replaced. The bridge intonation looks strange.
4. The string nut looks like it was replaced.
5. If the Gotoh tuners are original, it indicates this bass is not older than the mid-eighties. If this is the case, the serial number would have been originally stamped in the Ebony of the fingerboard directly below the 24th fret.
6. The wiring harness looks older than the mid-eighties.
7. Something is funky about the extra cut at the center of the tailpiece. I've only seen things like that in the scrap pile.
8. The logo looks genuine (and highly polished), but it's really off axis and smashed in on the left side.
These things night mean:
1. The bass was refretted at some point, and the serial number was sanded away.
2. The bass was made here by someone out of scrap parts and never had a serial number.
3. The bass was a Fernandes (though I've never seen a lefty) and later refitted with Alembic parts of various ages.
If you can find some of these other numbers, especially one under the pickups, it can help solve the mystery.
