The guy I bought the sign from flips houses. This sign was one of a couple of signs that was found in a house he purchased. He found some blank porcelain signs that were not finished signs.
It's possible whoever lived there before was a porcelain sign maker. One of the other signs I purchased is a blank Sunray oil lease sign. Just has the logo and says "Sunray Mid-Continent Oil CO.. Forgot to mention it is the rare one, it has the BLONDE Sunray logo!!!!