78 volt / amp gauge question

[Mbeef61]

I just picked up a 78. Gauges all work but are really rough. Has volt gauge.

I found locally a really good shape cluster that is in much better shape but has amp gauge.

Can I just swap my volt gauge into this better cluster? Am I missing something?

I know there is more to it going from amp to volt and have read up on that, but since I am already volt is it as simple as just swapping my working volt gauge in place of the amp gauge on the better cluster? Anything different in the circuit behind the gauge face?