I'm not sure of the date of death of Matthew AGNEW, but he died sometime between the time his will was written and proved.
Note: MATTHEW AGNEW was the s/o Samuel AGNEW and nephew of John AGNEW who died in Newton Twp., Cumberland Co., PA in 1783. MATTHEW AGNEW married two times:  Nancy RITCHIE  Rebecca FORBES Child from Matthew's first marriage to Nancy Ritchie was: Peggy AGNEW m. John Wynkoop.
Record of Pennsylvania Marriages Prior to 1810 Volume 1 -- Marriage Record of the First Presbyterian Church, at Carlisle -- 1785 to 1812-- 1808, June 9, AGNEW, Matthew, and Rebecca FORBES.
----------- Will Book L Page 326. Written: 16 May 1839 Probated: 14 June 1845
MATTHEW AGNEW - West Pennsborough Twp. Wife: REBECCA Sons: SAMUEL, JOHN, ANDREW Son JOHN was bequeathed the family Bible Daughters: JANE and PEGGY wife of John WYNKOOP Mentions: John FORBES, deceased ... Then will reads: "... and bequeath unto my said daughter PEGGY the shares or part of my deceased wife NANCY, (late NANCY RITCHIE daughter of ADAM RITCHIE deceased) which said shares or part will be ? on the decease of JANE WHITE, widow and relic of JOSEPH WHITE deceased and which is a part or share of the estate of THOMAS RITCHIE, deceased and now in the hands of JOSEPH LABUCK of Carlisle and as to the remainder of my Estate whether real personal or ? or whatsoever ? it may be, I do give, devise and bequeath to my said beloveed wife REBECCA and my sons JOHN and ANDREW to be Executed of this my last Will and Testament, hereby revoking ...... Executors: Sons JOHN and ANDREW AGNEW Witnesses: John Kelly, John Creigh