George and Mary Hammond mention their son, Chuck. They are played by Tom Bosley and Marion Ross, who played Happy Days (1974)' Howard and Marion Cunnungham. At the end of the first season of "Happy Days", eldest son Chuck went upstairs, never to be seen again.
TV Guide ranked this episode number 82 of the Greatest 100 TV episodes of all time, as of that printing [Special Collectors' Issue: 100 Greatest Episodes of All Time". TV Guide (June 28-July 4, 1997)].
Although the 1856 British Guiana stamp is the rarest in the world, the one shown on the picture is not it.
Another Happy Days (1974) reference: Mary Hammond played by Marion Ross mentions Lake Pfister. The name Pfister was used often in the series; it was the name of a frequently visited hotel as well as the last name of Fonzie's girlfriend, played by Linda Purl.