LeBeau and the Little Old Lady - S3-E25
Continuity mistake: When Newkirk and Carter are playing Gin, Newkirk puts a card on his forehead so Carter can't get it. When he puts it on his head, it's about a quarter inch below his hairline. In the close up, the card is now at the hairline. In the wide shot, the card is again about a quarter inch lower.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.