Yep and wires never go bad. Maybe I should have trouble shot this a little more but I have seen it a lot in this type of coil with cars. One cylinder no spark and move the spark plug wires and it follows the wire. Replace the wires and spark come back to all cylinders. I will step out of this one.
Cars have a kettering type ignition not a magneto type ignition.
If you have a polarity sensative induction timing lamp you can check this because the pick up has to be put back to front to get a reading on the - spark wire.
It is a single circuit with a spark plug connected to either end of the coil and the windings in the middle.
If one end is open circuit the whole thing is open circuit.
If both spark leads are connected to the same end of the coil, the one with least resistance will get all the spark and the other will get none.
You know electricity will follow the path of least resistance.
Some coils have an internal resistor so if a wire goes open circuit there is still a complete circuit but these are way too expensive for a lawn mowr.