Factual error: At the end, Sam reads a poem from a Mark Twain book and says, "Twain wrote it when his daughter died." But the poem, famous because it was engraved on the daughter's headstone, isn't by Twain, but by poet Robert Richardson. Twain never claimed authorship, so Sam couldn't be reading it with Twain's byline from any of his books. (00:48:00)
Factual error: In the scene where the guy is telling Machiko about the major league teams that wanted him, he mentions the Indians, Yankees, and Orioles. The episode is set in 1953 and the story is from before World War II. While there had been a minor league team called the Orioles up to that point, there was no major league team called the Orioles until 1954.
Factual error: Though this episode takes place on April 1st, 1969, a freshly-painted sign in the park contradicts the date. In the scene with the hippies in which Sam is disguised as a meditating guru, the huge sign just behind him touts the San Diego Centennial Celebration - in 1968. (00:16:00)
Factual error: At one point when Sam is visiting Delilah in the courthouse he is hugging her and the Sheriff guarding the door comes in and sees them. As the sheriff is leaving, he has a patch on his arm that says "County Sheriff." As this episode took place in Louisiana, there would only be Parish Sheriffs, not a County Sheriff.
Factual error: Al says he was an astronaut and flew around the moon, describing a mission that sounds precisely like Apollo 8 (10 orbits around the moon, reading of Genesis, etc). In the season 2 finale episode 'MIA, ' set in 1969, Al says he was shot down in Vietnam two years earlier, in 1967, taken prisoner and not freed until 1973. The Apollo 8 mission flew in Dec. 1968, meaning Al would have been a POW at the time. Also, NASA astronauts aren't generally sent to serve as pilots in active war zones.
Factual error: The episode takes place November 9, 1965. After the haircut incident they are seen moving away from a theater with Doctor Zhivago on the marquee, but the movie was released December 22, 1965, a month and a half after the scene is supposed to take place. (00:28:00)
Factual error: The episode takes place in New York in February. During the scene with the Beatles arriving at the theater, we see a tree that has very green and full leaves on it. Trees with green leaves are visible in other parts of the episode as well.
Factual error: When Sam knocks on Diana's door, she opens it. But we've just been told that she's completely deaf, so there's no way she could have heard him knocking. Though she dances to "vibrations in the air," this is with music played at volumes high enough to cause such vibrations. Sam is absolutely not banging on her door that loudly.
Factual error: When they arrive at the Federal Building, an exterior shot shows a green Karmann Ghia exiting with California license plate 1MMW713, except 1XXX plates first were issued in 1980. A blue California plate for the time should have been just XXX. (00:06:20)
Factual error: Sam is wearing a Casio calculator watch, which we are shown up close when he is driving the laundry van. The first calculator watch was made by Pulsar in 1975, and Casio's first calculator watch was released in the 1980s, long after this episode's 1973 date. (00:15:25)
Factual error: When the boys are talking to Jackie to get her to cooperate with their plan, the song Shake It Up by The Cars is playing, except the show is set at September 30, 1981, and the song was released in November 1981. And it wasn't a pre-release demo version on the radio since the song was still being mixed at Syncro Sound Studios in early October. (00:23:00)
Factual error: When Sam is in the library, there are multiple book titles visible that were published after the show's date of 1967. The clearest is when Sam and Duck tussle, the book "Men How To Understand Your Symptoms" falls on Sam - this book was first published in 1986. (00:29:00)