Do pie shells need to be Pat Yisrael?

Yes. A pie shell fits into the category of “pat ha’bah b’kisnin” (refer to OUKosher.com article mentioned above for a definition of this term) and therefore should also be Pat Yisrael. However, if one purchases pie shells that are not fully baked, then they will become Pat Yisrael when one completes the baking. One should not use non-Pat Yisrael graham crackers to make their own pie shells.