"Does the GCB require exact examples (or a reasonable facsimile) regarding denominations and colors of such?"

They require the exact piece. The ones going on the tables, the only difference is they are notched.

"Is a casino (in Nevada) permitted to have two or more denominations of the same color for NCV or cash value checks [chips] for any use."

As far as I know there are no restrictions on colors.

It looks to me like the plaques could have been used for the same purpose as the scanned Caesars chip. NCV and an expiration date. I do not know this as fact, just opinion. I have not talked to John Kendall about the plaques. If you had a customer with a credit line in the "Jillions", why not give him a $25,000 free play, to get him in the casino.