When I said square I was talking about your pump as apposed to the one with the cut off corners. You have either a M101E or a M101C. The only difference I can find between the two has to do with the pumping mechanism in the bottom of the pump, the outside is identical on both models.
Some information about the Gulf pumps. It has never been determined who designed these pumps, Gulf or the pump companies. Some of my parts manuals have "Gulf" printed on the cover, others just say "Gilbarco/Erie/Southwest, etc." I have Erie literature on a similar pump, one parts manual says Gulf, the other says Erie. My assumption is that Erie somehow was allowed to sell the pump to anyone. The Gilbarco literature just states Gilbarco, no mention of Gulf, so possibly this pump was offered to anyone, possibly as a low cost pump.
Incidentally, none of my Gilbarco literature shows the piece of trim that is at the bottom of your pump below the Gulf sign.
Author, Gas Pump Identfication books 1st & 2nd Editions & Air Meter Identification books
We rebuild ECO air meters and sell parts.