Alternator rotor - 1-phase vs. 3-phase (KZ650/750)

Does anyone have a spare alternator rotor (flywheel) from a KZ 650/750 or GPz750 3-phase permanent magnet alternator around? If so, could you do me a favor and count the number of poles on it?

If you place a screwdriver or such as shown in the pic below and drag it around the inner perimeter of the rotor you can easily feel and count the poles.

The 1-phase 650 rotor has the number 037000-1340 stamped on the back, i believe the 3-phase 650/750/GPz750 rotor should be stamped 037000-1530.

On my 650 I'm currently running a 3-phase stator (18-poles) with a 1-phase rotor (12 poles) and as far as I can tell it's working perfectly good (charging well, good spark, feeding my H4 headlight and Dyna-S without problems) - what I'm trying to find out is if there's any difference between the rotors used in a 1-phase system and a 3-phase system and if I would gain anything by switching to a rotor from a 3-phase system.

Since everything is working the question is mostly theoretical, I would just like to know - any input much appreciated, thanks.