Mills' Company was an independent unit from Monroe County. I have no information on it, but there is a file on the unit in the AL Archives. I don't know exactly what's in it, but county files may have correspondence from former members, contemporary correspondence such as orders or reports of elections of officers, transcripts of newspaper articles, and a great deal of muster rolls and/or other lists of members. So, it would be worth a visit to Montgomery to see what's there.