That was my thinking with my near 60 year old Land Rover. It's not used much at night time and in rain I have the option of using only one windscreen wiper. So far just needed a new regulator with pattern ones available cheaply enough.
Note you will always get a higher voltage from dynamo with it disconnected from regulator - that's why it's there. The 12.5 volts you are measuring are battery volts with dynamo making no contribution at all. If dynamo windings are intact and brushes ok try a new regulator.
