I just got home, but.....this is what I remember about Sally Stanford. (Valhalla Inn)
She was from Oregon.
Was a Madam in San Francisco 20's -40's. (Made a lot of $$$ and owned 4 houses there)
Was married 6 times (or more)
Sold the 4 homes and bought a mansion in Pacific Heights (San Francisco)
**** her manision was robbed by 5 guys in 1965 ( 2 of the culprits were SF police officers)
She also had a Tavern in San Francisco (don't know the name)
Her legal name was Marcia Owens ( sometimes spelled Marsha)
She got her name sitting in a dinner or bar listing to a song with Sally in it and looking at a newspaper article seeing Stanford beating Cal in the big game (Strange but true)

She bought the Valhalla in 1948 and sold in 1971 to Texas Oilman C. Harold Hobbs
In 1962... she ran for Sausalito City Council using her real name Marcia Owens (lost) I didn't see Mayor info, but stopped looking 1971 after selling .

I am pretty sure that there was gambling at this establishment......
But I haven't seen anything with gambling in any newspaper article so far.

There is also a Valhalla chip (yellow plain mold) on eBay. I can't confirm that either chip (plain or your circle in square mold) is from this place. But.....I can't deny it either. I would attribute them both "as attributes" until further info is confirmed.
Many chip companies used the plain mold....I believe Portland Card Co did as well. I believe David Spragg would have this info if it is available for both plain and Circle in Square.