That is correct. The part number of the regulator you removed was in 1973 parts book as used for all Chrysler alternators.
The '65 amp L/N' alternator listed in the '73 parts book was not made by Chrysler, but by Leece Neville and has slightly different wiring.
I took look at Hamtramck Historical's Library, and the '74 sales books list the alternator with defogger as '65 amp' like you found.
See page 15
The 1970 Hamtramck Registry - 1974 Dodge Dealership Data Book - Dart
It's a confusing naming convention and its not standardized.
If your car's alternator is original, the '74 Service Manual shows
View attachment 1716023377
Those tags made it easier than looking upo the part numbers.
Note these ratings are just names. They very roughly indicate the maximum that they can provide.
For normal driving, they only need to keep the car running, which is around 5 to 7 amps for your car.
With headlights, wipers, heater fan on, the demand will be closer to 30 amps.
The electric rear defroster draws alot of current just by itself, that's why your car got the optional alternator, heavy battery, and wiring modifications.
