Hello
I can only find info upto the 76 cars (using the manuals on the Australian RROC site). It seems that it may well have a separate voltage regulator. These are of simple construction (the wiring diagrams I can see even show the internals of the regulator). The regulator has an additional complexity as it feeds some sort of battery temperature sensor/circuit (take a look at the diags).
If your alternator is failing electrically, it can only be the brushes in the alternator, or a simple component within the regulator. Both should be easily fixed.
If the alternator is failing mechanically (a bearing), then you can get bearings.
What make is the alternator?
Cheers... Rob.