Walter Trager, played by James Gregory, addresses the apartment landlord as Mr. Moody, which happens to be the real last name of the actor playing the landlord, i.e. Ralph Moody.
James Gregory appears only this one time in an episode from this series; Cloris Leachman appears twice, her second appearance occurring later during this same season in Man in the Middle (1962). The careers of both would include many more dramatic roles in many more TV series, but they are both perhaps best remembered from TV sitcoms for the recurring roles Mr. Gregory had as Inspector Frank Luger in Barney Miller (1975) and Ms. Leachman as Phyllis Lindstrom in The Mary Tyler Moore Show (1970) and its spin-off Phyllis (1975).
Adjusted for inflation, the $150,000 Frank Nitti claims Walter Trager stole from the organization in 1932 would amount to approximately $3,420,000 in the year 2024.
Although both James Gregory and Cloris Leachman were prolific for their appearances in multiple TV series before and after the making of this particular episode of The Untouchables (1959), this is the only series in which they appear on screen together.