I would think that someone with the last name of Oster got a hold of that chip and scraped off the unneeded letters. Not an easy chip to find in the wild.

Did you know that a lot of the Tahoe Village Roulette chips ( Metal inlay) that are in many of our collections originally came from the Bill Foster estate. He had a stake in the Tahoe Village and got taken for a ride by the Stockton boys. He invested ( I am told a few million) and never made any money back.

But he had ended up with boxes of these old chips. They ended up going to one of his best friends (Walt) and then to another guy. He sold off many of them about 20-25 years ago. He does still have a few left. ....the story I am told anyway.
(Image from the ChipGuide)