Go Light on the Heavy Water - S1-E9
Continuity mistake: The boys are looking out the window at the mysterious truck. When the camera looks at them from behind, there's a building right in front of them.
Go Light on the Heavy Water - S1-E9
Continuity mistake: When the smoke bomb goes off, Klink has his monocle on. After the smoke really starts, his monocle is gone without being taken off.
Go Light on the Heavy Water - S1-E9
Other mistake: After the smoke bomb goes off in Klink's office, there is a shot from the outside where the boys get a blanket to catch Klink. If you look at the window of the office behind them, you can see the smoke coming out in an up and down pattern, suggesting the smoke to be coming from a rig controlled by an out-of-sight crew member.
Go Light on the Heavy Water - S1-E9
Visible crew/equipment: When the staff car entering the compound stops, you can see a reflection of the crew member stopping the car, the light rig, and the camera in the chrome.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.