The chip is real... here is what I posted on ChipTalk about 7 years ago:
“Just FYI...
This chip is in the book.
This chip comes from the 17th issue of Dunes chips, around the same time as all of the "golf course" chips that we are accustomed to seeing. There are 4 chips in this series, a $500 purple, a $1000 Yellow, a $5000 Maroon, and a $25,000 Lt Orange chip. They are all oversized baccarat chips and they are all encased in the lucite.
They were given to employees when they retired. The values listed in the book are based on their value while encased in the lucite. None of these chips have been seen loose. They were probably a backup set and for this reason, not many of them are seen for sale or available. The price ranges from $50 to $200 based on denom. and condition.”
Hope this helps...