Southern States Cooperative Sign w/chalkboard

I have a 14"x16" Southern States Sign with a built in chalkboard. Its a heavy metal sign with a chalkboard in bottom right corner. I got it in a thrift store for less than a tank of gas in my truck! I really like the sign but I sometimes sell to acquire new items. My fear is selling something rare, as I have not been able to find anything like it online. Or could it just be a sign that a certain location produced explaining its rarity? I'm am just turning 30 and getting into collecting so I would appreciate any advice!!

Thanks!!
Matt