Alternator Roundback . couple questions please.

Hello,

Can you make sure I'm on the right path and also answer a couple questions please?

Car: 1964 Dodge Dart, originally Slant Six
ENGINE: Now is a 1978 318 / 5.2
IGNITION HEI conversion and no ballast resistor
CHARGING: I have already routed the B+ to the starter relay and no longer to the Ammeter.

ALTERNATOR: Is a Roundback and has two FLD terminals besides the B+

Question 1: Being a roundback with 2 FLD terminals, what year range would this have been made?

Question 2: I know that one of the FLD terminals is supposed to be a + and other a -, which is which?

Question 3: Should I be using the replacement Voltage Regulator for the old charging system, like the VR128 or the kind for the newer charging system that has the flat rectangular look, triangle shaped plug with two posts?

I dont want to mess this up so I appreciate any step by step on guidance you can provide.

Kind regards,
Mark