As far back as the 1920's, glassware companies offered glasses, dishes, tableware, and just about everything they could think of, to service station operators to give away with the purchase of gasoline. These were all independent offers, and in one town a Shell station might be giving away the same thing a Sinclair station in the next town was. This was the same thing movie houses gave away on dish Tuesdays. These were generally generic items and did not have a oil company logo. What you describe sounds like one of these and was probably given away during the 1950s. Companies such as Anchor or Corning regulary advertise in National Petroleum News, offering their latest promotional items.
Incidentally gas was available during the war, you just needed ration stamps to get it.
Author, 1st & 2nd editions of Gas Pump ID book, 3rd edition is now available at
www.gaspumpbible.comAir Meter ID book also available