The Naturalization Act of 1790 says, "And the children of citizens of the United States that may be born beyond Sea, or out of the limits of the United States, shall be considered as natural born Citizens."
That is precisely George Romney's case. By that early congress's view he was eligible for POTUS.
“...The Naturalization Act of 1790...” was rescinded before 1800. So it matters not a tinker’s damn what it said over two hundred years ago.