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It is not preferred. In the 1980s, semiconductor technology had progressed to the point where internal VRs were available. . . .for watercooled cars with the alternator mounted on a bracket in the engine compartment with its own fan.

Our cars have the alternator mounted 2" above the hot engine, and the VR heat-soaks when the engine is turned off. Heat is the enemy of electrical components and the internal VR can be thought of as a giant, solid-state switch which generates its own heat.

I did a Club Race at Gingerman once, hauled there 14 hours, and had the alternator light come on in the race! I thought I had broken the belt so I immediately hit the pits. Turns out it was the internal VR in my alternator, throwing up its hands! When it cooled down, it worked again.

So if you have a 79 with an external VR, keep it as long as you can.