Thanks Linda so much for the articles. They make my instrument even more special.
The music store did get back to me, but they have no memory of the C.S. Jennings. The man who responded will pass on my craftsman's name to someone else just in case it rings a bell. The store is still run by a Gorby so its a family run biz I assume that has survived so far.
I looked up the address on Google maps and found a small house in what is now considered Charleston (between a church and a tatoo parlor). I thought it might be his shop but its a home with no outbuildings. Maybe he had a shop in the basement and sold the dulcimers out of his home and not the store, but bought a Mel Bay book from Gorby's for each customer. Or maybe #103 was his personal dulcimer. I'll never know, but being a son of an American Historian, I am pleased to play a bit of dulcimer Americana. Thanks again Linda and Ken.