Hi,
There is no record of Numa Leger/Leyer on Fold3, there are records for Jean Leger, Julian Leger and Louis Leger in Miles Legion.
"Miles Legion, A History & Roster" by Art Bergeron and Lawrence Hewitt, have him listed as Numa LEGER & rank of 3rd SGT on headstone.
However, his headstone image on Find A Grave has no rank indicated. I would suggest obtaining a copy of "Miles Legion, A History & Roster" via your local library and checking to see if there is any reference as to where the authors found this information.
My guess is that there is a hospital record book somewhere which will have some information, posting a request on the Mississippi site may prove profitable.
Alan Thrower
England