Artie's hands and face are dyed green in the last scene. The final freeze-frame shows his hands and face with normal skin color.
When Morn is explaining her need for "mildam", she casually hands Ben Victor a sphere of gold which, based on the scale relative to their hands, is somewhere around four inches in diameter. A sphere that size weighs in the vicinity of 27 pounds (troy weight) and could not be handled or passed back and forth that lightly unless it were hollow.
Near the beginning as the light that represents 'flying saucer' moves across the sky it disappears on the front of the livery stable barn instead of behind it.
Hellfire Simon uses the terms "outer space" and "flying saucer". The former term was recorded as early as 1847 by English poet Lady Emmeline Stuart-Wortley, but the region above the atmosphere was more commonly referred to as "the ether" (or aether) until the Michelson-Morley experiment of 1887 (at least 10 years after this story takes place). The latter term, however, did not come into use until the 1947 sighting by Kenneth Arnold (disc-shaped flying objects, however, had been reported, according to some interpretations, as far back as the Middle Ages). West's use of "flying saucer" at the closing scene can be attributed to Simon's earlier mention.
After West leaves the 'Pie Plate', when he walks into the bar while the people are counting their gold 'contributions', the shadow of the microphone is visible on the table in the foreground.
When the saucer door opens, the wires used to pull it up are visible.
The crooks behind this scheme somehow manage to possess a fortune (almost $5000) in precious gems, yet simply wish to give it away as bait to scam the townspeople out of the 2500 pounds of gold Jim West is transporting, which in 1870's gold prices would be worth about $825,000 to $940,000. It is overlooked that they have in their possession a small, easily-portable, self-sufficient and virtually silent power source to run all the outside blinking lights and the internal lighting system. It is more efficient and more silent than even the gasoline powered generators we have 130 years later. Such an electrical marvel as that would easily be worth an incredible fortune to numerous industries of the time. (It should be noted that Wild Wild West is filled with anachronisms - it is, after all, a fantasy program.)