Yes, your super 55 was originally only 6V. The amp gauge should work on 12 or 6 volt since all it measures is amps. But the factory setup is positive ground, so it would work backwards unless rewired. Most people switch to negative ground when they go to 12 volt. The lights were originally 6 volt and will burn out in seconds if run on 12 volts. Someone should have put a resistor in the ignition system to bring that back down to 6 volts so it doesn't burn up the points. 

All of the other original gauges were mechanical, so voltage won't bother them.