Producing just his paperwork is not enough. He also needs to cite a legal authority for the proposition that a person born abroad is not naturalized for constitutional purposes. There are many legal authorities that say a person born abroad, who is made a citizen-at-birth, is naturalized (Rogers v. Bellei, Miller v. Albright, Wong Kim Ark, etc.).
Citizenship is a question of both fact and law. I believe the facts are or can be established. What remains is to apply the law.
“Producing just his paperwork is not enough.”
Agreed. But the average person can grasp that quick enough and things get suspicious when even that shallow move is not taken.