Replaced the rotors on a 911 recently with Brembo cross-drilled rotors, and went looking to see which way the pattern went. MB has one direction and Porsche the other. But the set has the pattern different left and right, so then it became a question of which direction was "right" - and it turns out there is no "right" direction. The purpose of the holes is to allow the gasses generated by brake operation to dissipate "more quickly" than undrilled rotors, so it really doesn't matter.

'87 300D Turbo with only 282,000 miles
'83 911SC with really great brakes