Factual error: Cary Grant arrives at his Tokyo hotel two days early, and no rooms are available. He goes to his embassy, which, according to the sign on the gate is the "British Embassy". In reality, the sign would say, "Embassy of the United Kingdom of Great Britain and Northern Ireland".
Factual error: The uniforms worn by the engineering force are from the wrong era. Prior to 1941 the left arm rates had the head of the eagle pointing to the wearer's rear. Steve McQueen and the rest of the Engineering force rate eagle head is pointing forward, which is from WW2.
Factual error: Alva and Owen go see the movie "One Way Passage", released in October 1932. The movie takes places in August, the year is not stated explicitly, but there's a wall calendar in the dining room at the boarding house (you can see it when Legate leaves, calling himself a fink) for 1934, and at the same time the date shown in the office (when Redford sits at the desk to decide who will get pink slips) is August 14, Friday, which would set the movie in 1931.