I am trying to figure out if three individuals listed in the muster rolls for MS are a relative of mine.

I know that my great-great-grandfather (Morris Newton Acklin/Acklen) was a Private in the Civil War, Co. D. MS State Troops. I believe that he had a son named Aron Alexander Acklen (or maybe Aaron Alexander Acklen--unclear), who I think served, but I'm not sure. I have found the following information from muster rolls found on the internet/ancestry.com:

Aron A. Acklin, 24 MS Vols, Co C (Private)
Alexander A. Acklin, 36 MS Infantry, Co. I (Private)
Alex S. Acklin, 43 MS Infantry, Co F (Private)

I'm not sure how to best go about getting additional information and thought about requesting pension applications, but am I correct in thinking that pension applications could have been made from where they were living (versus where they served?) I'm not sure where this ancestor lived (I assume MS, but not sure) and haven't found him on MS census.

Thanks for any thoughts/guidelines!