On McGee's criminal record, he is listed as having no middle name. However, in a later series, it is revealed that is middle name is Farragut, which should have been listed on his record.
The NCIS team suspects the private investigator because he claimed to be on a stakeout for three straight days, yet his car was spotless in spite of rainstorms during that time. In the following scene, the team locates his vehicle. The streets are wet, and a car in the background has raindrops on it, yet the PI's vehicle is again spotless.
When McGee's information comes up on the mobile fingerprint scanner, it says he is blonde. Blonde is only used for females. Blond (without the e at the end) is for males.
Abby holds Mortimer the puppy up and says he's going to be a seeing eye dog. His vest clearly shows he's a puppy with the Guide Dogs of America school. That's a different school from the Seeing Eye school. She would have been more accurate saying Mortimer is going to be a guide dog (it's like saying all Kleenexes are tissues but not all tissues are Kleenexes). The terms are often used interchangeably, but Mortimer is going to be a guide dog, not a seeing eye dog (not with that vest).
Ducky wears a yellow, flowered necktie in one scene near the end of the episode. In his next scene, he's at the cemetery wearing a maroon tie. When he returns to NCIS after that, he's back in the yellow tie. It doesn't take long to change ties,; also, it would be in character for Ducky to wear a more sedate tie at the grave, then switch back to the yellow at the office since he's concealing his mourning from most of his coworkers.
Mrs. Mallard's tombstone shows her to be 98 when she died (1912-2010). However, 5 years earlier in season 2 episode 13, "The Meat Puzzle", Ducky tells Gibbs that his mother is 96 years old. Mrs. Mallard aged only 2 years in 5 seasons.