Malcom converts $40 to "14 pounds, 10 shillings and threepence three farthings," which is correct for the conversion rate of 1 GBP = 2.801061 USD at the time this episode aired. This is ~$300 in 2013.
As Opie is pining over Malcolm's departure, he tells Andy that Malcolm promised to show him how to make a paper ladder. This is exactly what happens in Malcolm's next appearance on the show in "The Return of Malcolm Merriweather."
Malcolm Merriweather comes from Heckmondwike, England, which is near Leeds.
At the beginning of the episode, the license plate on the car in Andy's driveway is DF 153. This is the same plate that was on the front of the Darlings' truck in "The Darlings Are Coming."
This episode possibly inspired the show-within-a-show that Jerry and George wrote as the pilot for the fictional NBC sitcom "Jerry" in The Pilot (1993), in which a man who injures Jerry in a car accident must serve as Jerry's butler to work off his debt.