Ah, wouldn't you have to take measurements on the bass and treble sides of the neck, rather than thickest point?
It should be 1-2mm thicker on the bass side by the looks of it, if you measure towards the middle of the contour (1/4 of the way in from each side of the neck). Should be easier to tell higher up the neck where it's thicker. You should be able to feel this though, especially if you can A/B with another guitar, otherwise you'll need some calipers or something I guess
Since it has the extra bulk on the bass side, it feels a little thicker in your palm while giving your fingers a little extra room to wrap around the neck on the treble side. Is how I understand it; it's been quite a while since I played this type of neck.
Oh here's another idea: trace the bottom of a mug (perfect circle) onto a piece of cardboard and cut it out. Make it a half-circle so you can hold it on the back of your neck. You should be able to eyeball it from there, to tell if the contour is symmetrical or not.