A potentially real (not 555 prefix) phone number with area code 910 was given in the movie. Not long after the movie was made, this area code was established for then central, now southeastern North Carolina.
When John Newland (Byrne) is outside in the stables talking to his wife Nancy, he is not wearing any neckwear. Yet in the next scene when they are inside, just before he confesses his secret to her wife, he sports a gray silk ascot tie.