You may have seen these encapsulated LV Hilton chips for sale from time to time... they were sent out as an invitation to the first New Year's party after the International Hotel became the Hilton. According to my perpetual calendar, the dates mentioned on the plaque were likely from December 1971, January 1972 not long after Kerkorian sold out to Hilton.

I had not seen one of these close up till I won this one on eBay. If you look at the scan of the back of the plaque, you can see they are really $25 International chips that have been drilled. On the front, casino Marketing has pasted some "made up" stickers to make them Hiltons!