I have not searched the James you are referencing but having gone over my notes from wills and deeds in my line, I think that there is strong and convincing evidence that this James is the son of John Fentress d 1733 m Ann Hopkins. The James whose will was rec in 1743 was the son of Michael Fentress. That James and the above mentioned John d 1733 were brothers. Here is the evidence connecting your James with John and Ann:
1. Ann was the daughter of John Hopkins. In John Hopkins' will rec 1736 he mentions his daughter and son in law as Ann Fentris and John Fentris- Note the i spelling which is consistent with the spelling of James' last name in the deed you referenced. This spelling is very rare in the PA Co records. Nevertheless, John Fentress ( the son in law of John Hopkins) spelled his name in his own will (1733) with an e. Note that John Fentress had been dead for 10 years when James Fentriss executed the 1743 deed- Perhaps James' mother preferred the spelling with the i that her father, John Hopkins, had used or perhaps James Fentriss was conveying property with a chain of title through JohnHopkins and was merely attempting to avoid any question that he is the proper title holder (thus, intentionally perpetrating John Hopkin's misspelling).
2. In John Fentress' will rec 1733 he names among his children, James, and devises to James 130 acres in the N. Woods near horse bridge & Sipors Swamp ( he also gave James a negroe girl with the name Bess- the name is hard to make out). John's will is found in DB 4-459.
So you have with the above a precedent for the i spelling (quite rare) and clear evidence that John d1733 had a son named James who inherited land from John in the N Woods ( the very land area mentioned in the 1742 deed). Taken together the evidence seems more than circumstantial that John d 1733 m Ann Hopkins is the father of the James in the 1743 deed. Regards, Gary.