I’ve noticed that on earlier Fender pickups the polarity of the pickups often varied from North to South and North again. I’ve seen old Telecasters with a North bridge pickup and a South neck pickup. The older switching and wiring on the early Centralab 1452 Lever switch didn’t have both pickups on at the same time. Maybe that’s why Leo changed from the blend control on some of the earlier instruments. If the pickups were magnetized out of phase than the instrument would sound pretty thin when both pickups were used with the blend control.

I’ve seen many early Stratocaster pickups made till around 1957 magnetized North. The pickups made from then until now have remained pretty much South. When the pickups are normally in the 2 & 4 position, either using a 3 position switch or a 5 position, the pickups are “In phase & parallel”. They are not out of phase in that position with standard pickup. During the 70s I started reversing the polarity and winding direction on the middle pickup to give a quieter humbucking effect in the Strat 2 & 4 position. Gibson has always made the adjustable pole side of the humbuckers South as with the polarity of P-90 style pickups. During the building of the Gibson ES-355 (Stereo) guitars, the neck pickup had a North polarity because it was to be used with a stereo amplifier. When using a mono cord plugged halfway into the jack, you would have both pickups operative but out-of-phase with each other.