Gilbarco made the 101 from 1939 to 1955. There was also a twin available. There 101 Model number was used on many pumps, more important is what follows the 101. The made a 101 A-1, 101- A-2, 101C, 101DC, 101DB-1, 101DB-2, 101DC-1, 101E, 101DE and actually all the Model Numbers began with a "M." All these models differ somewhat, the early ones have a square bezel around the face and the later models have a a bezel with cut off corners. My new Gas Pump book will have color pictures of two of the models.
Here is some information I have on the pumps.
http://petrolianacollectibles.com/gb%20101.htm

Jack Sim


Author, 1st & 2nd editions of Gas Pump ID book, 3rd edition is now available at www.gaspumpbible.com
Air Meter ID book also available