The other, major difference between the EB-2 and the Starfires was the pickup itself. The older Starfires originally sported a single coil Hagstom-made Bisonic pu.
The Bisonics sound completely different from the Gibson mudbuckers. They are not humbuckers, but big single coils. They are far clearer and have a broader response range than the Gibsons ever had. Think about the muddy bassline in the Animals' We've Gotta Get out of this Place (EPI Rivoli or EB-2 - not sure which). To me, that's the most representative Gibson humbucker sound. The Starfires were much cleaner.
When Guild inroduced the Starfire II, a second bisonic was added. My understanding has always been that Phil's and Jack's Starfires were the II's. They definitely had the bisonic pu's.
Here's where the Alembic lore kicks in (as usual). Over time, Ron and Rick worked some magic to hotrod the bisonics with the addition of a second magnet, rewinding to lower impedance and ultimately addition of Ron's emitter-follower circuit (arguably the first on-board active bass preamp). The sound of this generation of Alembic mods is on Crown of Creation and Live Dead. Later, as Alembic's experiments with pickup winding progressed, the hotrodded Bisonics were obsoleted by Alembic's own pu's.
Guild finally stopped using the Bisonics on Starfires and M-85s in favor of their own humbuckers. Their sound suffered. Since then, all the Guild and DeArmond reissues of the Starfire have one kind of humbucker or another.
Bill