I don't know if any of this will actually confirm the two women, it just seems to possibly connect some dots.
Records of Littleton, MA Gideon Powers b. July 28, 1731/-2; m. 1759 Ruth Hosmer, Acton. (p. 418)
Acton Marriages: POWARS, Gidion and Ruth Hosmer, int. Sept. 3, 1757. (p. 210)
Acton Births: POWARS, Ruth, d. Gideon and Ruth, May 1, 1767. (p. 90)
Nathaniel Powers, son of Ezekiel and Lucy Townsend Powers, b. April 27, 1760 married 1784 Ruth Powers of Acton. (p. 113) (p. 208) Neither page lists her parents. Mentions Blood’s History stating hse had 10 children – record lost, but it lists three Nathaniel, Ruth and Samuel. From: History and genealogy of the Jewetts of America
DAR.org lists Nathaniels wife as Ruth Powers b. 1767 died 1843>
http://services.dar.org/Public/DAR_Research/search_descendants/?action=list&MyPrimary_Seqn=802519&MyLineageCount=1
Findagrave has them as Ruth dau. of Gideon and Ruth, wife of Capt. Nathaniel.
Ruth Powers Jewett at http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=37456666
Capt. Nathaniel Jewett at http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=37456602