Although he is not depicted that way in the movie, Rev. DeLaine wore glasses.
This entire movie is set in the 1950's. However, in at least one of the New York street scenes, both the clothing on the pedestrians and the cars on the street appear to date from the late 1960's and/or the 1970's.
A few minutes into the second half of this miniseries, there is a stock shot of a subway in Manhattan. The subway train is from the late 1970s, though the action in the miniseries is from the early 1950s.
On the night that Buster throws a surprise birthday party for Thurgood, after he opens the door to their apartment, he walks from the foyer into the living room before turning on a light in the darkened apartment or removing his coat and hat, when a light switch is clearly visible just inside the front door.