Early Hamms Beer Sign

I just bought this sign last week in an online auction. It measures 13 inches wide and 6 inches tall. It’s a TOC sign from Donaldson Art Sign Co Covington KY. A few questions:
1. How old is the sign?
2. How rare is the sign? (I’ve never seen one before)
3. When did Hamms start using the slogan “Smooth and Mellow”. When did they stop using it?

I think it’s a rare sign with very little info on it. Any info would be greatly appreciated.

Thanks