Yes, he said that and he is dead wrong. He was neither the first to make such claims, and he is certainly not the last to do so. In fact, it is physically impossible for such a person to be a natural born citizen. The truth of that statement are the past and the present naturalization laws. No doubt you will dispute that, but try answering some questions.
Step 1. A natural born citizen cannot be naturalized as a naturalized citizen, because a natural born citizen is already a citizen and you can only naturalize a person who is an alien. True or False?
I also know that there are many legal opinions that agree that a NBC is someone born on US soil or otherwise into the allegiance of the US.
I agree that a NBC can not be produced by an act of naturalization created by congress and, if you agree with that as well, than you must agree that congress has no authority to define the term Natural Born Citizen in the first place.