Well, as it turns out, there was a mixup at the factory where these things were made and my mother's sisters daughter's uncle was working there at the time. Anyhow it seems that he was asked to take the prototype of a sign for Highway 11 to a customer. Eventually the mistake was resolved and my mother's sisters daughter's uncle kept the prototype...

I was thinking of putting it up on eBay but if anyone would like to make me an offer...