This features a guest performance by a real New York City police detective named Barney. Actor Barney Martin served in the NYPD for 20 years, including as a detective.
Harris's incredulity when he hears Andy call his editor "Lou" refers to the character of Lou Grant from two popular news-themed series contemporaneous to Barney Miller: the half-hour sitcom The Mary Tyler Moore Show (1970), and the hour-long drama Lou Grant (1977). Grant was played by Edward Asner in both, making Asner one of the few actors to play the same character across two vastly different styles of television.
Mr. Jessel of the obituaries column is appropriately named for George Jessel. The latter was a Yiddish comedian, frequently called upon to deliver eulogies at show business funerals.