The BLDCs I’ve removed from old HDDs mostly had 4 pins - they are wye (star) wound with the center point is brought out. When measuring those you can see nicely that one of the pins has half the resistance when measured against the others. That’s the middle pin.
I guess for motor calculations you may need the phase resistance.
But for the purposes of calculating your voltage limit to prevent things burning, phase to phase resistance is fine.
I’ve bought quite a few motors by now for playing with SimpleFOC and figuring out which is best suited. I can say that for motors in that price range, I would neither trust the listings to be correct, nor would I expect a lot of consistency from the motors themselves. Sometimes I’ve found 1Ω or more difference when measuring the different phase-to-phase resistances - of the same motor!