Give aways for the convention is my guess.
I have a Thunderbird Las Vegas advertising piece like this & I think a Harrah's. Harrah's did this promo stuff, some just were stickers on the back of an old silver dollar. Bars in Vegas did this too, I have one from Joe's Bar, later Longhorn Casino & now The Bighorn in North Vegas.

Dunes either sponsored or held the GE convention in June 62 as marked on 2 different colored diamond mold chips which are actually the first commemorative Vegas chips. These are rare $1 chips & reedemable at the Dunes Hotel.