Help! OLD Reverse Glass I. W. Harper Sign???
 

Does anyone know anything about really OLD reverse glass whiskey signs? We are looking for information on an OLD Harper Bourbon reverse glass painting sign that we found in Dad's garage. It has gold foil underneath it too. Says "I.W. Harper Gold Metal Kentucky Bourbon" on it. It is very ornate and the painting is very detailed. It is painted on a mirror background and looks like 5 coins with different pictures and sayings on them. I have looked and looked and can't find another one like it anywhere. Thanks for your help. :)