The fund would have been set up to cash in "outstanding" chips. There would have been a list of which chips were "outstanding". I have serious doubts there were any $500's "outstanding" after the initial count by AC Gaming.
It looks to me like AC Gaming turned their backs after the count and employees helped themselves. Similar to what happened at the Atlantis. The difference I see is the Playboys were not notched before the count as they were at the Atlantis. It is not easy to notch BJ chips and I doubt there is a machine in the area that would destroy them properly. In LV the only place to destroy BJ chips is at BJ. It takes two machines and is a two step process.

Could someone get one or more cashed?
Yes, because some low paid employee was not paying attention.