Here's what I can confirm about the token. I know it came from Las Vegas and was obtained while I was attending a NEXPO Convention of Daily Newspapers. I am almost certain it was included in a gift bag all the convention attendees received upon picking up their credentials for the week-long confab. Also, included in that bag was a grouping of casino chips that you took to each vendor's booth and used them to play games of chance for prizes -- like Black Jack, craps and roulette. Everyone who played won a prize -- I just kept a few of the chips and tokens.
Here's two I brought home because they were cool looking:

Thanks for sharing your information. I am not sure we can ever tie these Bally tokens to the casino, but I do know for sure that there was a giant gaming room full of all the new coin-operated electronic machines at Circus Circus where you were awarded tickets to exchange for merchandise.