The doctors knives are one of very few models that don't come in D2 but I have heard from people in the know that the doctors knife will be avialable in D2 soon.
If it is marked ph-d2 then you know it is, and otherwise it is stainless.
Also it has been found they like Schatt & Morgan(sister brand) are now mixing steels which means on a 2 blade knife one blade may be carbon, and the other stainless. For what reason not sure but that is what they have been doing lately.
Hope this helps.
Larry