Squareback vs round back alternator?

New parts. Very few new products are made as well as the factory parts. :(
I would only replace damaged or worn parts.
If you have to use that coil and ballast resistor its probably OK. Original resistor specification was 0.7 Ohms?
Do you have a photo of the current coil and connections?

Found just a photo of an original 1960 engine compartment. But can't see all of the wiring.