Roger Healey plays stand-up bass at his party, an instrument actor Bill Daily played in real life, along with acoustic guitar.
The establishing shot of the big department store where Jeannie goes to shop is the May Company on Wilshire Blvd in Los Angeles. No longer a department store, the building now houses the Academy Museum of Motion Pictures.
The title refers to the mod or MODernist subculture that originated in London, England in the late 1950s and peaked in the early to mid 1960s that was typified by fashion, pop music and British beat music.
Also the same Department Store where Jan Brady gets here Brunette Wig
The girl in the department store who compliments Jeannie on her choice of "mod" clothes for Tony would get to meet him a couple of seasons later. Billed only as "1st Girl" here, the actress would return as "Susie Schaeffer," Gen. Schaeffer's daughter in Jeannie, My Guru (1968).