From the following source, G.W. Gentry is buried in the White Oak Cemetery in Neshoba County. He is listed as a member of Company I, 40th. MS Inf. Should you decide to order his records you may want to include a look up in this unit as well.
To confirm the burial data above, I suggest posting a look up request on the Neshoba County message board. There are several people with access to a Neshoba County cemetery book at this site. You may want to include his two wives in this request.