Although it is established that Bruno Raphael is Susan Graham's grandfather, in real life Harold Gould (1923-2010) was only 26 years older than Belinda Montgomery (b. 1950).
Seaview Reunion: Del Monroe (Ramsey Tate) and Arch Whiting (Paul Emmons) were both regulars on Voyage to the Bottom of the Sea (1964). And Christopher Connelly (Eddie Graham) has an uncredited role in that series' first episode.
The phone number of the repair shop (555-2368) must have some special significance in the movie/TV industry. Many times this number is seen in different movies and television series (also as area code 311-555-2368).