Jim;
They are more like early slot cards.
Those shown in the above posts were followed by tickets that were issued by the slot machines
based on the $ amount of play. In Laughlin
you would see them in use on many machines, great sport was to go down a row of open machines pulling off the tickets left behind by players that did not know about the system.
The tickets could be cashed in at the Slot Club for Hats, Jackets, Etc.
Jim