The second time Clay's Grille was mentioned, Perry's regular hangout in the ninth season. Here, the doorway is shown but not the interior.
This episode is one of several in the early seasons of the series where Della continually refers to Perry as "Mr. Mason" and not "Perry."
When Robert Dawson comes to Perry's apartment, he shows Perry a $10,000 bill to be given Perry in case he needs to provide Dawson or the veiled lady legal services. Perry said he had never seen one, and little wonder. The $10,000 bill was the highest denomination currency ever issued for general circulation by the U.S. Treasury. (A $100,000 note was issued only for transfers between Federal Reserve Banks.) The $10,000 bill was discontinued in 1969, and since then the $100 bill is the highest denomination of U.S. currency.
Carol Stanley and her lover Robert Dawson both drive Pontiac Star Chiefs. His is a 1954 four door sedan; hers is 1957 convertible.
This is a rare episode without a scene of a court trial or any sort of legal proceeding.