Alternator/Voltage Regulator/Never Mind
 

Just picked up an '81 300D and trying to sort out any issues with it. Noticed last night that while idling the red battery indicator light flickers. Idle the engine up and the light goes out. The idle speed appears to be normal, so I don't believe low idle could be the cause. So, I'm wondering if it's the voltage regulator or the alternator that might be becoming a problem?

Car only has 57,600 miles on it, so I wouldn't think the alternator was going out...but then it's probably 24 years old, too. The previous owner probably thought the alternator was going bad because there is an alternator in the trunk that looks like it's new. Still, the VR would be an easier and cheaper fix if folks think that might be the problem. As an aside, I've only driven it once since the car isn't registered, but I didn't notice any lights flickering or a dim/bright condition which I might normally associate with a voltage regulator going bad.

Will appreciate any insights folks have.