A 6-screw trem is really 2-point, as it should be set up so that it's the two outer screws that it all pivots on. But the two-points have thinner knife edges, so they are a bit more accurate.

Technically, as long as the bass post is in the correct position on those Wilkinson trems, then the post distance can vary by that amount, but that is rather stretching the reality of the situation that if you've got post holes 30mm either side of the centre line, and not 28mm (bass) and 32mm (treble) then it will be all wonky. It's the truth, but not the whole truth.