It depends on the state. In MN, the law is, the pump doesnt need any labeling for ethenol blended gas, because its required to be blended, by law. The only pumps which are labeled are the pure gas pumps.
In WI, its just the oposite...ethenol pumps are labeled and pure gas isnt.
The easiest way to figure it out, is to ask the owner or manager of the gas station you go to. They would be able to tell you the state laws concerning this.
Its interesting that as you go up in altitude, the need for high octane is redused. I just went thru the mountains in CO. and every pump had a 85 octane pump. I asked at the gas station, and they said as you go up in altitude the air pressure drops, and so does the compression in the motor, there by reducing the need for high octane fuel.