Primarily Petroliana Shop Talk Forums Shop Talk Petroliana Forums General Petroliana Discussion Holes in a 48" Chevy OK sign?

I bought this 48" Chevy OK used cars sign this past weekend, and it has 4 small holes in the center of the sign that are original to the sign. The reason I am assuming they are original is that the porcelain lines the inside of the holes, unlike the ones that have holes created/drilled.

Any idea what they would be there for? I have not seen many 48" OK signs, so I'm not sure if they mounted differently or what?