You are asking whether there is a type of genetically imbued knowledge or externally implanted knowledge, I think, because everything else that we know, we learn as we go... either by school or parenting or experience or (as we mature) logic.
I think that with our current knowledge of brain function, your question (as phrased) is true. Not all knowledge can be known a priori. In fact, so far as I know, NONE of it can be a priori.
I say that because while we have the ability to learn, we don't know exactly how that works. So we have no conscious knowledge of the "owner's manual" of how to operate our brains or bodies. We do it but without conscious knowledge.