Very pretty bass. Looks to be in a good deal better than average shape for a 30+ year old semihollow. I think a lot of Starfires have crazy glued bridge pieces like yours. If the break was clean (the rosewood saddles dry out pretty evenly, often shearing neatly along the grain with no other damage), the repair may hold forever (rosewood likes superglue) and the sound may be indistinguishable from the original.
The best thing about your bass (apart from its nice condition) is that it's intact. I believe the knob and small toggle hieronymous mentioned do look stock (unless there's something about them I'm missing). The knob should be master volume and it's intended to be a totally different knob style from the other, Guild logo knobs. I've been searching the world over for that specific knob for an M-85 without luck. The small toggle is the infamous bass boost/tone suck switch, which moves between the two foregoing settlings. A lot of Guild basses have the switch. Many people find it less than useful because, although each setting produces a different and interesting tone, moving between them tends (in my limited experience) to require a fair amount of EQ'ing to get each to produce a good tone (Specifically, the tone suck side requires extra bass, so when you switch to bass boost, the boom is disturbing).
As to the pickups, they are the (somewhat) less distinguished Guild humbuckers that followed when Guild stopped using the fabled, Hagstrom bisonic single coils. If you would prefer the earlier sound, Fred Hammon has faithfully reproduced the bisonics, calling them Dark Stars. They are a drop-in, totally reversable mod for Starfires with your style humbuckers.
The Let's Talk Guild forum is currently the best Guild forum around and is where the real experts hang out. They can help you with more info if you post your Starfire over there. Nice bass, and welcome to Alembic-land.
