Except for the birth episode (#120: "And Baby Makes Four, conclusion"), this is the only one with a scene featuring an actual baby as one of the twins - presumably the boy since the crib is trimmed in blue. (Episode #124: "Is This Trip Necessary? included an hallucination where one of them appeared as a baby alligator.) The boy's name would eventually be revealed to be Zachary. This meant that retrospectively How Green Was My Valet had two characters named Zachary.
The closing "wrong number" scene is a remake of the tag from the original pilot "Mr. Big". Retrospectively this makes it almost a bookend for Get Smart as this is the seventh-to-last episode of the series.
The naming of the ambassador's assistant "Zachary" is an apparent reference to guest star Jonathan Harris's most famous role as Dr. Zachary Smith in the TV series Lost in Space. His appearance in this episode also marks a reunion with Don Adams as both had earlier co-starred in The Bill Dana Show. In a further coincidence, Julie Bennett, who plays Zachary, previously appeared in Episode #66: "Supersonic Boom", in which Dana had a cameo.
For his guest stint Harris had narrowly missed director Tony Leader who had directed the just earlier two-parter "House of Max" as Leader had directed Harris in two episodes of Lost in Space including the first broadcast episode which also introduced audiences to Harris as Dr Zachary Smith.
