Claridge's opened in 1981.
Per Bud Jones, the green lettered chip was not manufactured until 1987.

What $1 chip was in use from 1981 to 1987??

I wonder if the brown chip was once in play and then it reverted to the back up when the new ones were delivered.
I find it real hard to believe they would bother having a purpose made backup rack of $1's which cost way more than $1 each to produce.