On page 39 of
FMEA third edition under 10) Potential failure Mode it states "However, in preparing the FMEA, assume that incoming part(s)/material(s) are correct."
It also states that exception may be made.
So unless you have already identiified deficiencies in incoming part quality why would you include incoming in a
PFMEA? Most companies cannot afford the cost of incoming inspection and work with their suppliers on a "ship to stock" basis.