I was told they were Montana chips, somewhere around Missoula. I found a Monta Club in the 1950s in Martin City, a couple hours north of Missoula. No idea if this is the same place.

I was also lead to believe the Shamrock Club chips were local to Montana as well. As you can probably guess, every state had a "Shamrock Club" so I don't know if it would be possible to place these chips with any one of them.