Help ID this Michelin Sign Please

My dad and I ran across this pair of Michelin signs and just want to get an idea of when they were made. They're a little rough, with the coating chipping off, but they look cool. Anyway we're just curious when these were produced and what kind of value they have. Any help is appreciated!

 

By the way, they measure approx. one foot wide by 6 feet tall.

 

Porcelain on steel, I think.

 

truck radials....signs can't be THAT old