In the records library, where else?

It says "Card Room" on it. Card Room in LV speak has always meant poker room. Pan was played under the poker room supervision in most casino's.
Chips that said "Card Room" on them were never cashable or playable at other casinos like normal rack chips.
Good only at the issuing casino.

The Four Queens had them and they were not even playable in their own BJ or craps pits.