Yes he is! Arnold was born in Hawaii, and as a child moved to Austria. Once Arnold figures out how to work a printer he'll be happy to show you the proof.
If someone was born in Hawaii and two days later his parents took him to Afghanistan where he was trained by Al Queda and indoctrinated to believe that he was sired by Allah to destroy America the left would insist that he is still a natural born American citizen eligible to be president. Some on FR would agree with them.