Did gamblers in the Old West cheat ? You bet (no pun intended) they did !  In fact, a whole industry developed to help the cheaters.
Every device invented to prevent cheating was modified so it could be used to cheat. So does that mean all Gamblers were cheats?
No! The honest gamblers were just that, honest but they had to know how cheaters cheated in order to keep from going broke.
Men like Wyatt Earp, Bat Masterson and Luke Short were famous for playing on the "square" and winning. Let me also add Doc Holliday to that list.

Gaffed equipment can be found in the old manufacturers catalogs from that time period. These manufacturers openly advertised there, "Advantaged Cards" and "Loaded Dice", just to name a few.

Harry Brolaski wrote in his book, Easy Money, c1911 " I assert, without fear of successful contradiction from those who know, that not one professional
gambler in a thousand is at all times absolutely square".

Remember, to gamble, means to attempt to win something for nothing and when you gamble on the "Square" the odds are against you. Since the early days of steamboating on the Mississippi River a lurid feature of that traffic has been gambling. Estimates place anywhere between 600 and 800 professional gamblers plied their trade on those boat during the period leading up to the Civil War. Canada Bill, a well know con man, went as far as offering a boat Captain $25,000.00 a year for the opportunity to work his trade unmolested. To the credit of the Captain, Bill's offer was declined.

Keplinger Card Holdout

In the games of cards you can be cheated by bottom dealing, the spread, marked cards, hold outs,
reflectors, shiners, ring-coat spider, bug and a hundred other ways.

In the game of Faro a skillful dealer may use cards that have been nicked on their sides so that with his finger he can tell what the next card out will be. Or, by simply using a gaffed dealing box to control the cards order of play. Loaded dice inserted into any of the games of Craps, Klondike, Chuck-A-Luck, Grand Hazard, and so on would ensure a profitable night for the House or the individual player depending on who brought the dice to the game.

While thinking of it, wheel games like Roulette and Wheel of Fortune were rigged with a "squeeze" brake
on the wheel or with magnets.

Keno was controlled by the "keeper" and his gaffed Goose which controlled the order that the balls fell.

Even Chuck-A-Luck was rigged using electricity.

 It is no wonder then that these crooked games were considered the "real" gold mines in the
 mining camps and cattle towns.