Thanks to everyone for more details and background. Mystery and lost history.

I can't understand which it is. A race course chip, that was made but never used? Maybe a promotional chip. And maybe made by someone else as a commemorative?

No matter what, a couple I knew said they got it at the race track. How or why or what for, I have no details?

They were good regulars at the Chinese Restaurant and when I said I collected casino chips, they gave it to me. I can't add anything factual other than their gift, and how they said they got it from the Arlington Park Race track.

I mean, honestly it could have been for a free hot dog, or parking or just something that was given away as a trinket. I have no verifiable evidence of what it was or how they came to owning it.