I'd venture a guess that very few people collect Gas Pump Seals. In California the Agricultural Commissioners of each of our 58 counties make the seals and test the pressure/functionality of the gas pumps. Presumably since the Commissioner can also weigh a basket of broccoli and determine how much it is. Weighing live lobsters, a little trickier. So seals can also be found on all supermarket scales! Good luck "harvesting" any. It is a felony to remove one! You will be sent out into the fields to pick cotton or caterpillars or something for 6 months. The color/design changes every couple of years. Best chance of success is to find an abandoned gas station and peel away!

The Commissioner has a little white truck with tanks that hold a gallon of gas, and when he visits a gas station, he pumps a gallon from each dispenser. And the gallon he gets better darn match the amount shown on the gas pump . . . or else! (I once owned a gas station and know!)