My grandfather grew up outside of Midland, SD and is just about 94 years old now.I asked him about your C.O. and thought you'd enjoy his response:
I don't know what happened to him and I don't remember the girls, but my mom worked for six months or so for Charles.He was always referred to as C.O. Davidson.I didn't even know his first name was Charles.The regular clerk had an operation or something so Mom was just filling in.
My Aunt Alice [BENSON married Miles CONNER] worked there [the hardware store] for several years, but I think that was wen Behl owned it.