I spent 4-5 hours today in the city of Benicia, Ca going through phone books, directories, and other resources. The only bummer was that they didn't keep anything pre-1969 .
I did however find a little info on a couple of places. The following ad is from Gambling Scene Magazine May/June1980 (so we know it was open 73-80+??

I did find the listing in the phone book in 1973 but not in any year prior. . Pete Fett was not found listed. I also didn't have any phone books from 74-83.

This location became the Sundowner. The first listing I see is 1984.(I couldn't check 74-83)

This is what the building looks like now.