Sounds like a matter of definition.
Your statement "There wasn't an external resistor but the coil had resistance in the primary windings so it was the same as the coils you buy now that say no external resistor required. The resistance is internal." is correct.
However, comparing HEI system to the old points system seems to me like apples and oranges. Appears to me that any coil that will work, as designed, on a 12 volt tractor without extra external added resistance is a "true" 12 volt coil for that circuit.
Contrary to what many guys seem to think, there are no separate resistors in any coil from the points ignition era. A coil is a transformer with one end of primary and one end of secondary tied together. The designer controls the voltage or current capacity by the ratio of primary to secondary turns, the number of turns and the type of wire used.