This is the third and final appearance Jack Warden makes in the series. In each appearance, he plays a different role. His earlier appearances occur in The George 'Bugs' Moran Story (1959) and Head of Fire: Feet of Clay (1960).
The statement Walter Messlinger makes about forming a friendship with Hans Eberhardt is reminiscent of the statement Rick, played by Humphrey Bogart, makes to Louis, played by Claude Rains, at the end of the classic movie that also deals with Nazis: i.e. Casablanca (1942).
This is the eighth of eleven appearances Joseph Crehan makes in the series, each time playing a different character.