George Martin is exactly right in indicating that you need to provide the name. I am puzzled, however about your comment that Footnote.com not having any roster information on the 5th or 6th Louisiana Cavalry. I suggest you check this again as I am able to access many of the names on the rosters of these two units on footnote.com. As George indicated, the National Park Service Soldiers and Sailors list provides rosters, and you can also access the Andrew Booth Compendium of Louisiana Confederate Soldiers on line (www.youngsanders.org).

It is clear that no single source of rosters is going to complete as so many records were destroyed during and after the CW. Also there are known cases where a volunteer served with a given regiment for extended periods without enlisting - I know of one specific case in the 2nd Louisiana Cavalry, CSA. If your GGGGgrandfather's name is not on the rosters of the 5th or 6th LA Cavalry, it could easily be that the record is lost or destroyed, that or his officers did not keep complete and accurate records.

Hope this helps

Don Parker