Keep in mind that gasoline tends to pretty much all come from the same place. You basically have the branded manufacturers who sell gasoline they refined themselves (i.e. Mobil, Shell, etc.) and then you have a bunch of stations who buy from whatever refiner has the best price that day (Joe's corner gas stations, and many branded gas stations as well).
If you see a Mobil truck at a Mobil station you can be "pretty sure" it is gasoline refined by Mobil. But many Mobil stations can buy from "whoever" as well.
Based on that, I'm skeptical that you truly found ethanol-free gasoline, unless they have their own refineries in place or order a custom-blended gasoline (which would require its own distribution network). Read the fine print super carefully and be skeptical about this claim.
And you can try asking the people that work there, but in many cases I would also be skeptical that they really have a true grasp of what you would be asking them...
-Bob C.