Good question.
According to the notes attached to the code, the law was enacted in 1952. The specific subparagraph (g) was changed from:
(prior text) a person born outside the geographical limits of the United States and its outlying possessions of parents one of whom is an alien, and the other a citizen of the United States who, prior to the birth of such person, was physically present in the United States or its outlying possessions for a period or periods totaling not less than ten years, at least four of which were after attaining the age of fourteen years
to
(current text) a person born outside the geographical limits of the United States and its outlying possessions of parents one of whom is an alien, and the other a citizen of the United States who, prior to the birth of such person, was physically present in the United States or its outlying possessions for a period or periods totaling not less than five years, at least two of which were after attaining the age of fourteen years
According to the bios of Stanley Ann Dunham, she lived in the CONUS from 1942 to 1960. (17.5 years -- 3.5 years after her 14th birthday). She supposedly graduated from Mercer Island High School in Washington State (a fact that should be verifiable). She moved to Hawaii in 1960 and supposedly attended the University of Hawaii at Mānoa. Again, a fact that should be easily verifiable. If she completed classes for even one semester, then she met the criterion of four years of residency after her 14th birthday.
If, on the other hand, she didn't, then there might be a case to be made.
But that, actually, could be a really good point because there is a potentially exploitable hole.