I recall that station as well as a couple of others that were in West Valley I think one was on 4800 south if I'm not mistaken I only remember them because you didn't see many with a rainbow compared to the Chevron, Sinclair, Circle K and Texaco's that were common there were also Holiday Gas stations I didn't like going there because I hate clowns
but I think one Rainbow station was near one of the Holiday Stations possibly on 3500 south but it was around 25 years ago when I was a Boy and thought I a pretty important guy when my Mother had me fill up the car so I could be mistaken?
I'll check with some family out there and see if anyone might have anything your looking for it's a long shot I'm sure they all think I may have spent too much time near gas fumes and hence the collecting Habit I have they may be right but who knows may be a possible explanation but it's most likely the time I spent there with my Grandfather up in Idaho that caused it but if they have anything I'll let you know.
Good Luck!
Bob