that grommet location is the same as the Shell Green Streak pump sign, Shell bought Gasco & Gasco was headquarted in Oregon the same as the seller-
sellers description:

Here is an original Gasco Motor Fuel Sign. 12 inch round. Its a rare one & pretty much is what it is & it exists. Has chipage in porcelain as u can see in the pics. Take a look & see what you think... cool

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RANDY