This Isaac Van Metre/Meter is the subject of a major section of the 1909 Genealogy of the Duke-Shepherd-Van Metre Family.
"Isaac Van Metre (John^), son of John and Margaret Van Metre, b. circa 1713, probably in Somerset Co., N. J., called in his father's will "my eldest son" (Johannes being deceased), d. in Frederick Co., Va., ante 1748; m. Elsje (Alice) Scholl, of Somerset Co., N. J. (Records Raritan Church at Somerville, N. J.), circa 1736. John Van Metre in his will imposes upon his son Isaac the condition precedent to receiving his legacy, that Isaac shall sell his land on the Monocacy (Md.), etc. It is shown by the records that Isaac and his wife subsequently conveyed a tract of land called " Isaac's Inheritance," containing 200 acres, situate"
In 1745 John Van Metre (Isaac's father) included an infant Jacob in his will as follows:
"Also I give Devise and bequeath unto my said son Jacob after my wifes Third part of my Movable Estate and Legacies are paid an equal proportional Child's part arising therefrom as well as my lands which are to be disposed of ... "
If this is the only Jacob born circa 1745, then he is Isaac's brother, not his son. (Subject as always to more careful checking.)