The Heartsill book covers the Lane,s Rangers really well but this was a volunteer group out of Marshall, Texas, that simply took the name of Lane he wasn't a part of it. Lt. Col. Lane was commander of Lane' Brigade. The info given indicates the buried soldier was in Co A of several companies of a Brigade, not in a vol. company. My ggfather was in Co F of Lanes First Texas Partisan Rangers. I found that from National Archives and Texas. Also in 1850, 60, 70 and 1880 US census - nothing else . He is not buried with his wife who receieved a pension. He died in 1892; her in 1935 but where is he buried? He was Joe Hewitt, my namesake.
If the grave marker looks to be done by an organization, check with some organizations that keep records