I have just come accross a 1989 caesars palace $500 house chip. this chip is not listed in the chip rack. It is listed in james campiglia's book but states none known in any collection. this chip was used on the tables in 1989 and was in play when the movie "Rainman" was filmed there. the Rio opened the next week and these chips were too close to the $1 rio house chips, so they were pulled and destroyed. This is so far the only known example.