I actually have a number of similar chips. I wouldnt dream of trying to sell them as I don't believe for a minute they are real. I kept them in my collection as I can't cash them

This is where the $20 came from, just after the $1's were released
http://www.chiptalk.net/forum/chip-identity-value/53066-mismarked-ac-borgata-chip.html

Now, if you know anyone at the Borgata well enough, you could ask the poker room about the woman who was caught twice swapping inlays at the table, and they wouldn't cash her chips. Maybe she is a relative

Read the whole thread. All I said was it is impossible to prove 100% that it is genuine.