After Commissioner James Jeffers (Richard Anderson) is in a fight, a red scrape is revealed on his forehead, over his LEFT eye. In later scenes, when he appears with a bandage on his forehead, the scrape is now on his forehead, over his RIGHT eye.
At 17:36 and 17:51, the exact same Mexicans run down the exact same hallway for the second time.
The leather case with wire that West used to escape from Hassan's house/lair was never on his belt until he got to the cupola. When West was tied with his hands around the rod (after being gassed), there was no leather case on his belt. Also, when West shot the 'hook' into the wall across the compound, the leather case came off his belt, so he would have lost the end of the wire, and not been able to attach his end somewhere in the cupola.
When Betsy first meets West and Gordon, she her father's told her so much about them. But just a couple moments before she entered his office, Gordon introduces Jeffers and West to each other.
When West is tailing the boat, he gets out of the water and is wet. When he gets on the stagecoach and is behind the driver, he is dry.
At the end, when Tucker throws the lantern in the office to burn up West, Gordon, and Betsy Jeffers, the lantern goes behind some wooden boxes; however, the flames actually start in front of the boxes. Even if the kerosene in the lantern had spilled out in front of the boxes and ignited, the flames still would have started behind the boxes first, before traveling in front of the boxes.
Artie thumbs through a scrapbook that shows photographs and notes of him in various disguises in scenes from previous episodes; such as his disguise as Lt Greely as he stood in the Colonel's office from the episode preceding this one. Since the pictures are of him in disguise on locale, it is unlikely for there to have been a photographer on hand to document each of his personas while he's supposed to be undercover.
As Jim and Arty flee the fire, the fire is against the far wall, and a small fire to the right and closer to the camera. It is obvious that this is a pilot light because one Jim and Arty leave that stage, the whole area to the right burst into flames all at once. Fires will not spread like that unless an accelerant is used (in this case it is obvious that the fire is a controlled propane gas fed fire). Otherwise, the fire would have continued to spread steadily, but not all at once.
Towards the conclusion, Jim knocks on the door of Abdul's house. A guard goes to the door and opens the "speakeasy" peep door in the door. Jim throws a punch through the peep door, knocking the guard back and away from the door. Jim then opens the door, enters the room, and fights everyone. BUT the purpose of the "speakeasy" peep door is to see who has knocked and if it is then safe to open the door itself. However this is undermined if the door is NOT locked. Then anyone could come in at will and would not need the doorman to clear them before opening the door. If that were the case here, then Jim could not have entered the house and saved the day! So, why have the peep door. Just have Jim open the door (which is what he eventually does anyway) and beats up everyone.
Jim enters Abdul's foyer and fights everyone. Eventually, down to the last bad guy, Jim punches him and knocks him back and into the adjoining room, where two more bad guys become aware of the commotion. But as the fighting was in the next room, how could they have NOT been aware of their impending doom? Surely they would have heard the fight, investigated the noise, and joined in to eliminate that threat. They don't, and Jim and Arty vanquish the bad guys and save the day once more.
The boll weevil, which is central to this episode, did not enter the US until 1898, long after the time period depicted in this episode. Even if the intent was to introduce this pest, most people would have been unaware of its existence at that time.
When Jim rides up with the stagecoach, the other driver (whom Artie was supposed to take back to Sausalito) can be seen suddenly ducking down out of view inside the stagecoach.
Jim jumps into the water to trail a boat to see where it is going. But he dives into the water right behind the boat and no one in appears to hear the splash as no one turns towards the sound of the splash.
When Jim jumps into the water to follow a boat, he grabs hold of the stern and is pulled with the boat through San Francisco harbor. But the waters of San Francisco harbor are known for being notoriously cold (one of the reasons the Federal Government decided to put a Federal prison on Alcatraz: If one could get out of their cell, cell block, and through the fences, one would, in all probability, die from hypothermia from the cold waters). Yet not only does Jim not suffer from hypothermia, he is completely unaffected by the severe cold of the San Francisco harbor (a most unlikely scenario which would have spelled the end of the episode as well as the series).
When Artie is paging through the book of disguises, he turns the page after Jonathan Greeley, and the new page is obviously blank. Artie then goes on to describe Jake 'The Piano Player' in Deadwood, as if that disguise is shown on the blank page.
In reviewing his past disguises, Gordon says Paolo Martinez is age 33, while the book of pictures he is reading from clearly indicates his age as 35.