Perusing the Fiend Folio on page 208, I note the following:
A graft is not a magic item: It does not radiate magic once completed, it does not count against a creature’s limit for magic items worn, it does not have a caster level, and it is very hard, if not impossible, to salvage as treasure. It does, however, count against the treasure value of the creature with the graft, which means that creatures with grafts are still appropriate challenges for their normal Challenge Rating, but have reduced treasure.
Some grafts can replicate magical attacks for which saving throws are applicable. Although with respect to the above it would appear spell resistance is not applicable for the target who is resisting the effect of the graft, is this correct? I have examined the 3.5 accessory update which contains updated information for the Fiend Folio however nothing is mentioned in reference to grafts.