Metal Over Cardboard Eisenlohr's Henrietta Cigar Advertising Sign

This is a 13 by 9 1/2 inch metal over cardboard advertising sign made by the American Art Works of Coshocton, Ohio. It is self framed. The condition is very good. On the back there are instructions by the American Art Works, embossed in black ink, for cleaning the sign if it becomes soiled. The cardboard backing is still well attached to the metal and has an attachment that can be pulled out to make it a standing sign. This attachment has never been used. The colors are vibrant and there is no rusting. The sign does have some slight bowing and does not lay perfectly flat on a flat surface. I am wondering when this sign was made. I was thinking maybe sometime before 1930, but I am just guessing. Can someone help me? Thanks.