Nevada gaming regs are unclear on this subject.
Chips and tokens must be used for gaming purpose's.
Interpetation: If they are not on the tables, they are not being used for gaming.
This kind of leaves it up to the agent you happen to ask.
In 1995 I talked to the agent in charge of enforcement. I wanted to notch chips and sell them in the gift shop. I was told absolutely not.
I wanted to mail chips and was told absolutely not.
I could encase them in lucite and sell them. No other way. Selling a cash value or ncv in the gift shop was not allowed.

I do know of Nev casinos that are doing both. Maybe they did not ask gaming. Maybe gaming is not aware of these cases. Maybe they are.

As to your thought of cage accountability in Co. There will be no problem accounting for over face sales in Co or anywhere else for that matter. The cage's job is to account for money.