Link on Partial Leather:
986faq
If I remember correctly, on partial leather seats only the back part isn't real leather. And the steering wheel should be leather, but not the airbag.
You could order the 986 with almost every part you touch in leather, my car even has leather wrapped air vents. The problem is that finding or replacing these leather parts is next to impossible, because they never show up used, and I don't think you can buy most of them from Porsche. I haven't been able to find a Graphite Grey leather wrapped key surround anywhere, for instance.