Continuity mistake: A flashback episode set in the 1840s opens with Ben Cartwright as a first mate aboard a clipper ship. Rear-screen projection shows an ocean and a grey overcast sky. In a shot of the crew on the rigging and in the crow's nest, the sky is deep blue with a few white clouds.
Factual error: In a flashback episode set in the 1840s, Ben Cartwright and his former Captain are operating a ship's chandler business. A competitor accuses them of running a "flea market." That term is a translation of the French "marché aux puces" and did not enter the English language until 1922.