A couple things stand out here on these signs, way too nice is one, the font of all the writing looks a little "off", no "real" date and manufacturer company name, and I think the back being "blank" is odd. Usually backs are white or black on a single sided sign. With all of that being said I do think this sign could have been made by an actual company that made "real" signs at the "time". I can imagine the porcelain sign guys getting run out of business buy the cheap and flimsy new wave "plastic" signs.
