Foster's Club has been listed as "Foster City, California" in The Chip Guide, Dick Staeffler's California Card Room, and Armin"s California Guide. I do believe with that the RED Foster's Club chip is from Foster's Big Horn Rio Vista, California.
After talking to the curator of the Rio Vista Museum a few months back ( before Christmas), he sent me an email confirming that The chip was from this club.

Foster's BigHorn
143 Main st
Rio Vista, Ca

**notice the same curving letter design on the red chip and die.

These are pictures of the chips and dice in his collection along with part of the email sent to me. I tried to crop out his contact info. He has zero interest in selling or trading any of these items. believe me....I have tried.(He's a historian...these have way more value than money to him.)