Rockford's D.O.B. is 7/14/1929 according to a close up of his driver's license, which makes him a year younger than James Garner.
Bob Hastings does the answering machine gag at the beginning of the show. He plays a salesman selling funeral plots. In The Great Blue Lake Land and Development Company (1975) he plays a salesman who sells worthless desert property to potential buyers.
The real Malibu Lake is featured in the episode. This was a man made lake created in the 1920s where waterfront properties were sold while the dam was being completed and before the lake contained water. It took nearly four years before a heavy rainstorm allowed the lake to fill for the first time.
The character, Meyer Ziegler, talks about wanting to emigrate to Israel and being denied. This appears to be based on the real-life mafia figure, Meyer Lansky, who similarly tried to emigrate to Israel in his later years, but was denied entrance by Israel, and deported back to the U.S. This was similarly depicted with the character, Hyman Roth, in The Godfather Part II (1974).
Despite appearing in numerous pivotal scenes towards the end of the episode, including her own wedding, the character of Veronica Teasedale conspicuously never utters a single word of dialogue.