I will leave most of your questions to an AC collector.

Can the chip be reproduced or copied?
Technically yes as I can not find Limited edition on it.( I am looking at a scan.) I seriously doubt that they would or could, ever re-issue the same chip.

Can it be authenticated?
Not sure what you mean here.
No doubt that Caesars issued it. They would have a release signed by Cher. Paul-Son would require a copy before they made the chip. The release would state how many could be made. My guess is Caesars either made all they were allowed to or could have possibly made half and are intending to make a 2nd different chip in the future.