1998 Jeep Grand Cherokee, 109K mi, 6-cyl, Check Gauges light

The "Check Gauges" light came on for the first time. The volt-meter guage was pegged to the right (+) and stayed there for about 4 minutes. The guage then returned to the center/neutral position and wavered a bit more then usual, but stayed in the normal range. I cleaned the battery terminals and the car was able to start with normal gauge indications.
Just checking to see if this is an indication of an alternator issue or possibly a voltage regulator.

Thank you!