CSM?

If that is short for company sergeant major... you are wrong. They didn't exist.(at lest not according to regulation - can't rule out that it is possible to find one somewhere...)

The sergeant major was a Battalion position and there was just that one in a Battalion.

It was the "orderly sergeant" (a job not a rank) who was responsible for drill and discipline in the company and that was handled by the First Sergeant (a rank) Who ran the company during its daily routine.