Pretty much everyone who was everyone (or no one) in the '60s has a cameo, from Lance Loud (of the proto-reality TV show "American Family") to David Weisman, director of "Ciao Manhattan" (1972), the seamy, quasi-biographical film about Sedgwick's druggy collapse in which she starred.
There's the occasional goofy grace note: Kyra Sedgwick, playing a voracious and obviously Anglo television reporter named Suzie Morales, rolls the 'R' in her surname as she signs off, just in case someone missed the point (we've all heard it).