One of young Ducky's speeches is filled with several amusing ironies, such as him stating he finds bow ties unfashionable and that he hates working with dead bodies (up to this point, he has only ever been known as an M.E. who seems to love his job and wears a trademark bow tie). One of the more obscure ironies is when Maggie suggests he starts wearing a bow tie because he shouldn't go around looking like Doctor Who (2005). During the recent Matt Smith era, bow ties became the most distinctive feature of The Doctor's style and in fact, "Bow ties are cool!" was one of his catchphrases. Also, during 1968, when the flashback is set, the Doctor Who (1963) at the time was the second Doctor, portrayed by Patrick Troughton, who frequently wore bow ties in the role.
The song "Time of the Season" is a song by The Zombies, featured on their 1968 album, and based on the hair styles, indicates that the flashback was in 1968.
In the flashback scenes, David McCallum's character (Ducky) wears a turtleneck. Aside from the "Beatle" haircut, a turtleneck is one of Illya Kuryakin's trademarks - McCallum's role in The Man from U.N.C.L.E. (1964).
McGee is chided by both Gibbs and Tony for acting like an "overprotective big brother" toward Abby in "So It Goes." In real life, Pauley Perrette (Abby) was born in March 1969, more than eight and a half years before Sean Murray (McGee), who was born in November 1977.
Alice Krige, who plays Ducky's former girlfriend, also played the Borg Queen in Star Trek: First Contact (1996). The Borg Queen was reprised in Star Trek: Voyager (1995) by Susanna Thompson, who portrayed Gibbs' ex-girlfriend Lt. Col. Hollis Mann.