While the ring Laird Fergus Douglas (i.e. Fred MacMurray) gives to Terri Dowling (i.e. Anne Francis) may not be a real Douglas clan ring, it has the real Douglas clan crest inscribed on it. The motto, as pictured on the ring says: "Jamais Arriere." The Douglas clan stems from nobility and has a long history in Scotland, it's early ancestors fighting along the sides of William Wallace and Robert the Bruce for Scottish independence. The inscription, written in heraldic French, because heraldry originated in France, means "Never Behind." The other parts of the clan crest pictured on the ring are of a hat on which is perched a salamander enveloped in fire.
Though he voiced the Scottish brogue in the first two episodes featuring Fergus, Fred MacMurray is largely dubbed by the much deeper voice of English actor Alan Caillou in this episode.