It's a former Arco station, and the owners merely painted over the A and the O to make it the "RC" gas station. (That's why the price sign still looks very Arco-ish, although if you look real close, you can see that the Arco logos have been painted over on each grade.)
A commenter on this story at SFist notes:
I think the station owner is full-on insane. She drives a big S-class mercedes, painted metallic purple. I stopped buying gas there when I saw her verbally abusing one of the employees.http://sfist.com/2010/10/07/sarah_palin_event_banner_at...