The largest pyramids were all built by the old kingdom, did the later kingdoms still know how they were built? If not, assuming the old kingdom had archived "blueprints", could later kingdoms have read and understood them?
I touched on this in Is it true that "two hundred years after the last pyramid was reared in their country, Egyptians were as baffled by the big masonries as everyone else?" See the Herodotus quotation in particular, as he claims to have been told how the pyramids were built. (The accuracy of this knowledge is questionable, needless to say.)