According to Mary A. Hansard's "Old Time Tazewell," Margaret was visited in the summer of 1841 by her (grand) nieces "Eliza and Mary Chamberland," from Knox Co., TN.
Noting that William Graham had freed most of his slaves and given them land and provisions before his death, Hansard observes (p. 6):
"After the death of Mr. Graham his widow would send them money and pity the poor creatures. She was of a very sympathetic disposition and was kind to the poor and assisted them greatly."
Although Margaret apparently did not emancipate her own slaves (Eliza, Cynthia, James, and Stephen) before she died, much of her will does indeed consist of bequests she made to them as the end drew near.