Looks like one to me. I do know there is one on some school in SFO that's just kind of there sitting on the corner of the roof (dismounted may I mind you) for no explainable reason that I know of. Don't remember the school name. I know it was an elementary school however.
UPDATE! I found a Mobil Directo near Centennial Road Public School. OG Tweet said: There used to be a Cold War era air raid siren tower located on the northeast corner of the property of my elementary school, Centennial Road Public School. If it's worth noting, there are three poles at the aforemen...