right you are - there are 3 different ventilation types in use - straight or curved vanes and now 'pillars'.
Both straight vanes and 'pillars' are non-directional - but the curved vanes are directional.
Here is the Brembo explanation:
Curved vane disc should be installed with the vanes running back from the inside to the outside diameters in the direction of rotation.
Orienting the disc in this manner, creates a centrifugal pump. The rotation of the disc causes air to be pumped from the center of the disc, through the vanes, and out through the outside diameter of the disc. This enhances the disc’s ability to dissipate heat. On some OEM applications, this standard is not satisfied: the use of directional discs means to manage two codes (left and right) per axle with some extra cost therefore it happens that a car manufacturer can use the same disc with curved vanes on both sides, losing part of the benefit in balance with lower costs.
However - the instruction sheet I have with the Brembos I put on my Supra (installed two years ago) - say exactly the opposite.... and the picture of the install is exactly the opposite... hmmmm....
Now it looks like going with the pillars (non-directional) is the latest thing....
good catch