[cjshaker]

I would certainly replace it and not just bypass it. My 'newer' '60s vehicles use them to drop and regulate voltage to 6 volts, but yours, with the car already being 6v, apparently just regulates. Gauges are sensitive pieces and don't like an overvoltage situation, which can blow them.
You may get away with it for a while, but eventually it'll cause a major issue and you'll be looking for new gauges.
You probably already know, but be very careful with that wiring! There's a 99% chance that the sheathing has gotten brittle, and trying to move or bend them won't end good.