Goofs

When Detective Lassiter finds the bullet that killed the first reenactor he picks it up using metal tweezers. Neither police nor medical examiners retrieve bullets using metal tools because it could damage and or alter the striation patterns that are used to identify which gun the bullet came from.

During the initial conversation in the crime room, the armorer states that a bullet from the previous weekend must have got lodged in the barrel. Then a blank was inserted and that was enough to trigger the bullet. These are muzzleloaders, so the blank would have been inserted down the barrel in front of the bullet. It is impossible for a blank being fired from further up the barrel to force the bullet out of the barrel. If anything, it would drive the bullet further down the barrel, away from the muzzle.

The jeweler tells Henry that the original inscription he chooses for Shawn's watch adds $210 to the price at $4 per engraved letter. The original inscription, "Shawn, Don't lose this watch. Henry Spencer" is 34 letters so the inscription should only cost $136. Even if the punctuation is charged at $4 per mark that would only bring the total to $144.

When constructing the model battlefield Shawn says "Factoid! A musket is accurate form thirty yards." The word factoid means something that is *untrue*, but Shawn uses the information as if it is true. However, in North American usage it can also be synonymous with "piece of trivia".

During the opening credits, the secretary who sits down looks right into the camera.

When Shawn and Gus are walking down the to bridge to meet Lassiter, on the other side of the tents several white production trucks are visible.

At the beginning of the episode, Shawn unwraps a sandwich from "Mr. Sub", a Canadian sandwich chain. This is because although the show takes place in Santa Barbara, CA, the filming took place in Vancouver, BC.

Gus says the Air Force wasn't formed until World War I. While it certainly was not around during the American Civil War, the United States Air Force was actually formed as a division of the U.S. Army in 1907 (as the Army Air Corps). However, it did not separate and become its own branch until after World War II in 1947.

When Lassiter arrests the dentist, he says "You're under the arrest for the murder of Nelson Poe." He should have just said "under arrest" but the flaw wasn't caught and the scene was left in.

Shawn, wearing his Civil War-era Union Army uniform, purports to have been promoted from "Lieutenant Crunch" to "Captain Crunch." Captain Crunch is a naval captain, and a promotion from lieutenant to captain in the navy would be quite the jump, particularly for someone wearing the wrong service's uniform.

Shawn cites the events depicted in Glory (1989) as an example of African-Americans fighting in the Civil War. However, this film was about an all-black regiment, meaning it is historically inaccurate for Gus to fight alongside Caucasian soldiers, thus there is no sense in Shawn's argument.