Factual error: At the mint, Arte hides in a broom closet. He carries nothing in (nor did he hide anything in there beforehand), yet he emerges later in an "old man" disguise, wearing a wig, hat, mustache, false nose, glasses and janitor costume. Magic closet?
Factual error: The small round table in West's railcar parlor has a flip-over top, with secret maps hidden on the underside. The wine decanter and glasses all stay attached when it flips. But impossibly, when West turns the tabletop back over at the end, there's a full cup of coffee sitting on it.
Factual error: Artemus opens a cabinet to reveal a map of the United States where he and West are keeping track of the alphabetical murders. The map is far out of date for the Grant administration, with what became the state of West Virginia during the Civil War still part of Virginia, and missing entirely the states of Nevada, Oregon, Kansas, Nebraska, and Minnesota-all of which were part of the union before President Grant took office.
Factual error: West and Artie are trying to move a cabinet from the wall. A closeup shot shows West's left hand entering from the right side of the shot to press a button that allows a secret panel to open. Unless West twisted his left hand 180°, then him pressing the button as shown is not possible.
Factual error: Fenlow begins shouting about "one nation, under God, indivisible." This series is set in the 1870s. The Pledge of Allegiance, from which these lines are taken, wasn't written until 1892. And the words "under God" weren't added until 1954.
Factual error: The coin Artemus hands West is a Morgan silver dollar. It's no coincidence that the actor's thumb covers the date on the coin in the inserted close-up. The series is set during Grant's presidential term in the early 1870s, and Morgan dollars weren't minted until 1878, after Grant had left office.