Sounds like you definitely have a 51, or later model COE. Does it have "Chevrolet" emblems on each side of the hood, or large "5700" etc ? Does it have pull down type door handles, or push button type door handles? A 47, or 48 will have the fuel tank, mounted on the passenger side frame rail, and a 47 has a one year only dash, that doesn't have the notch at the lower portion between the gauges.
