On Brian Lawson's site you can see John Kinvig's will, which has been transcribed 1854 Arbory.
Brian has also a reference to the will of Margaret 1843 Arb, but there seems to have been mislabled as it is the will of Mary Kewin of Andreas.
Also there are wills for a Thomas and and for some Elizabeth Kinvigs that have not been transcribed yet, but which you could order and view at a Family History Center.