Factory ammeter

gm1236 said
This car also has a single pole ballast resistor, shouldn’t it have a dual being a ‘75?

I beleive you are correct. However the second resistor, which was 5 ohms, was to regulate power to the ECU. Later ECUs, and most (possibly all?) replacments today handle this internally.
But it does suggest someone has done some rewiring.

gm1236 said
Could this alternator that’s acting up be a 65 amp?

Some of the 60 and 65 amp alternators had different voltage regulation wiring than standard Chrysler alternators.
All cars equiped from the factory with 60 or 65 amp alternators had a heavier output wire and a grommet through the firewall as part of the arrangement.