I talked with the VP of table games yesterday. He told me that there were 6 people involved with the artwork on the Grand Opening chips. Each denomination of Grand Opening chips will have different initials on them. They represent those 6 people. 4 chips 6 sets of initials. Some have 2 sets of initials.
The $25 and $5 GO chips have them on front and back sides (different)This is the story I am told.

There are also NCV chips...not released yet.
$100
$500
$1000
$5000
For high rollers only...doubt any of us will ever obtain them.