An effort was made to drop the "North" from North Dakota in 1989.
Leo (John Spencer) claims that the U.S. spent millions of dollars developing a pen that would write in space while the Russians just used a pencil, but this account is inaccurate. Development of the space pen was independently funded by inventor Paul Fisher, who sold them to NASA at $6 apiece. The Russians began buying the same pen a year later. (Prior to adopting the space pen both countries had used pencils in space, but this practice was abandoned due to their flammability and the risk of tips breaking off and floating around in microgravity. Graphite conducts electricity and could short-circuit electronics.)
Originally, Jessica Yu was set to direct 'We Killed Yamamoto,' however Thomas Schlamme, anticipating a late delivery of the script before production and thus less preparation, offered to take her place instead, and reschedule her directing for the next season. Yu accepted and Schlamme ended up having less than two days of prep before shooting.
CJ (Allison Janney) calls Simon (Mark Harmon) "Agent 99", referring to the more competent associate of the protagonist of Get Smart.
Fitzwallace (John Amos) claims that if Bonhoeffer had been successful, the Germans would have built a statue of an assassin. However, pacifist theologian Dietrich Bonhoeffer had nothing to do with the July 20 attempt on Hitler's life (although he was falsely accused of this by the Nazis). The key conspirator and would-be assassin was Claus Schenk Graf von Stauffenberg.