Lorenzo Dow McPherson of SC/AL/MS

Seems there are at least 2 Lorenzo Dow McPherson's. MY interest is the one born in SC, 1806 married to Rebecca Ann Savage. My particular interest is their son Joel A.McPherson, born 1829 Laurens SC. I have Joel A McPherson Civil War Service record(Wayne MS) but it says his age is 16. I am fairly sure this was a mistake. According to info I have found Lorenzo D McPherson had 5 sons who all served in the war and 2 did not return. I think the Joel A whose record I have is one of those sons. How can I prove it? I found his widow Amy Moody McPherson almost next to LD McPherson in 1866 in Wayne Co MS. Grateful for any suggestions.
Jackie