Dick Van Dyke personally said, in a 5 episode program that he hosted on Nick-At-Nite (just before TVLand was created), that this specific episode, Where Did I Come From? (1962) is his all-time favorite that was filmed for the show. The four others are It May Look Like a Walnut (1963), The Attempted Marriage (1962), I'd Rather Be Bald Than Have No Head at All (1964) and Never Bathe on Saturday (1965).
This is the first flashback episode that shows Rob and Laura not living in their New Rochelle home. Future flashbacks will be inconsistent with the established facts of this episode regarding where Rob and Laura live before Ritchie was born. In the season five episode Fifty-Two, Forty-Five or Work, they are already living in the New Rochelle home when Laura is about two months pregnant.
On December 14, 2018, CBS aired a colorized version of this episode along with Never Bathe on Saturday (1965), in an hour long special.
In the flashbacks, the office is similar to the one in the first / pilot episode. Among other things, the door is in a square corner - in the newer and regular office, the door is on a angle. Most of the differences involve the furniture, but the windows in each is clearly different than each other too. Later documentaries said that the earlier footage was shot on a different sound stage.