Offhand, I don't know if that's an issue; most coils have 1 or 2 ohms impedance, though some electronic ignitions--like Pertronix--spec a 3 Ohm coil (I
think, don't quote me on that
). but I've run for years on (what I believe) are original coils in my BN2 and BJ8, both with Ignitors. Coils will heat up at idle, but shouldn't ever get 'pistol hot.' If a points gap is set up seriously too narrow the coil would heat up, but the car likely wouldn't run decently anyway.
Unfortunately, quality on aftermarket electronic parts has suffered for decades; last I checked, it's almost impossible to get quality points (for ignition and fuel pumps). Coils may not be an exception.