I don’t know if this will help, but you may want to look at the 10th Mississippi Infantry, Company G. I had four relatives in that company and know it was raised from Itawamba County and that they fought at Shiloh a few weeks after the company was raised. E. G. Betts was the first company Captain; he later left the service for medical reasons. There is a W. J. Smith (note initials reversed from your Smith) listed in the roster information I have, but I have no further information on that individual.