This marks the return of William Talman as D.A. Hamilton Burger after a ten months absence. He was fired from the series in March 1960 under the morals clause of his contract (he had been arrested when the police raided his friend's home), and after ten months Talman returned to reprise his role for the remainder of the series' run. William Talman missed only 12 episodes.
The "greenbacks" referred to in this episode are large-bill US currency that was removed from circulation in the late 1920's.
A character is asked to pick out an acquaintance from a stack of photographs. The top photograph is of actress Fay Spain, who appeared in the episode, "The Case of the Fiery Fingers".
In addition to the return of Hamilton Burger, this episode also marks the return of Connie Cezon as Perry's oft-mentioned but seldom-seen receptionist Gertie Lade. Gertie had not been seen on the show for two years prior to this appearance...and after this appearance, she would not be seen again for another three.
William Hopper and Cathy O'Donnell passed away about five weeks apart in 1970, each at a fairly early age. Hopper was 55 and O'Donnell 46.