No it about which pole is leading the other. It been very long time since I had the papers on this [kinda wish I had scanned them] but old cast iron points engine had to magnets polarity reversed in order to work with the new magnetron coils. Basically they old points system was a positive ground system and new system uses negative ground system [ie NPN transistors don't work with positive grounds.].
A good example of this is a horseshoe magnet. if you flip it the polarity on the left changes to what previously of the right and vice versa.
