This is a different kind of review (although this is one of the better Dragnet episodes). As noted in the trivia section of the IMDb page on this episode, this show featured black real estate professionals, which was rare for a late 60's show.
Jack Webb, who has the reputation for being starchy and conservative, was actually quite progressive for that time period. If you watch Dragnet regularly, you will see black real estate agents, judges, lawyers, doctors, and nurses. Black criminals are somewhat uncommon. In one episode, the Lieutenant giving directions to Sgt. Friday is black, and Sgt. Friday is clearly displaying respect.
Moreover, the black professionals portrayed in the show are not stereotyped. They are well dressed and clearly well educated.
Yes, at times Dragnet can be inadvertently campy (e.g. "Blue Boy"), but we should also note Webb's willingness to portray blacks in a positive manner (and to make them the victims of crime, rather than the criminals).