The way I see it, if nothing else I figure the burden of proof is upon the claim that a particular (or any) rotor is cast with perforations in the disc face. So far all the available evidence shows that they are drilled. While you can't truly prove a negative, the scientific method says that the best theory is that all perforated rotors are drilled until somebody can provide a documented example of one that isn't.
In the big picture though, it really is just trivia. All rotors are not of equal quality, be they plain, slotted, or drilled. I have no problems with anybody choosing to go the drilled route, I just think it's a good idea to be aware of what you are gaining (less wieght) and what you are losing (increased risk of rotor failure) and every big kid can make their own choice.
Bottom line is that it is always a good idea to buy quality rotors. If you want drilled rotors it is especially critical to get the best quality possible.
The SHW manufactured BMW Motorsports rotors, such as UUC offers, are one of the good safe choices, no matter how they are made.