To be fair to Bosom Buddies, a theme song does not have to fit exactly into a show’s plot. For example, Woke Up This Morning has nothing to do with gangsters, it’s about a domestic abuse victim killing their husband. But the lyrics are vague enough that it fits into the show amazingly well. The other song which was considered, Elvis Costello’s Complicated Shadows, mentions gangsters in it’s lyrics, but it just wouldn’t have worked IMO.