I have not read all the posts but this should be the same family written about in "Sketches of the Olivers" by Colonel Hugh R. and Margaret T. Oliver. They talk about this letter on page 250.
We are also involved with the Oliver DNA project at
http://freepages.genealogy.rootsweb.ancestry.com/~gaoliver/O...G.C. Oliver
gcoliver3@hotmail.comAthens, Ga.