Thats strange. I got the April 2009 issue here in the UK and it definatley has version 6 pro on it. I've installed and been using it.  Theres a picture of the box on the disc cover.

Wonder if its diffrent in other countries. Sure its digital arts mag you saw and not computer arts or something. I know I've mixed them up before today as they all look very similar on the shelf.

If you have no sucess with that keep an eye out for another new mag thats out, 3D Artist. the first issue is out over here now. thats got it on as well.