Factual error: At the movies, Magnum is watching a movie with Bette Davis, the first one she played in, "The Bad Sister" and comments "Keep it up, old girl, you just might have a future as an actress." Funny, but the dream is set in 1936, not 1931 when that movie came out. Implausibility of finding it in theaters aside, by 1936 young Bette Davis had already won her first Oscar. (00:30:30)
Factual error: When Blackthorne is on Rodrigues' ship, Rodrigues offers him grog. But grog was only invented in 1740, by British Vice Admiral Edward Vernon, whose nickname was "Old Grog" because of his preference for coats made of grogram cloth.