Continuity mistake: In flashback, we see the one-armed man kill Helen Kimble by striking her with a heavy lamp. All through the earlier seasons, though, we were repeatedly told that Helen had been strangled. (00:28:50)
Continuity mistake: Throughout the show's early episodes, Helen Kimble's dress on the night she was murdered was described as blue or blue-gray. Here, in the flashback to the murder, she's wearing an evening gown that isn't blue or gray, but pink. (00:27:45)
Visible crew/equipment: The tailgate of Lloyd Chandler's station wagon, and the door of Gerard's car a few minutes later both capture reflections of studio lights and the camera crew. (00:04:50 - 00:07:10)
Continuity mistake: The one-armed man orders Chandler to get up off the ground. In close-up, we see him sit up. But in the very next shot, he's flat on his back and sits up again. (00:11:50)
Revealing mistake: The last scenes of the grand finale/climax occur in an abandoned amusement park that's supposed to be in inland Indiana. But several shots with the Pacific Ocean "lurking" in the background (despite the cameraman's best efforts to hide or avoid it), as well as palm trees, and ocean sounds intruding on the soundtrack, reveal that the actual shooting location was in Southern California. (00:37:15)
Answer: Production vehicle models aren't in sync with the calendar year. The '65 Mustang began production in March 1964 and first sold in April 1964, before it was "introduced" the following year. I don't know which model was seen in the episode, but the 2+2 fastback was sold in September 1964. The 1964 film "Goldfinger" uses a 1965 Mustang as part of Ford's product placement. Basically, in the 1930's, FDR ordered automakers to release vehicles in the fall of the preceding calendar year "as a means of facilitating regularization of employment in the industry." Now, automakers can release new models as early as Jan 2 of the preceding year.
Bishop73