The Mendon VRs report the birth date as "24 Mar 177[torn]"
FindAGrave memorial, Kingsley Cemetery, Townville, Crawford County, Pennsylvania, USA; documented at FindAGrave.com, memorial number 158255355, created 16 Feb 2016; from Pennsylvania Death Record.
Headstone Record, Union Cemetery, Moriah, Essex Co, NY, documented at www.FindAGrave.com, Memorial number 95175915, created by Candy Rypczyk, 11 Aug 2012.
The Barber Genealogy gives a birth date of 1892, in disagreement with the headstone and the Social Security Death Index, both of which give a date of 1893.
1850 Federal Census, Eden, VT, pg 118 of the Ancestry.Com census images, shows Nelson W. Wheelock, age 17, living in the household of Walter and Salome Wheelock.
Nelson's death record indicates that he was age 33 when he died 3 Dec 1863.
Massachusetts Vital Records, 1841 - 1910, Lawrence Marriage Record, Vol 406, Pg 304; online database at www.NewEnglandAncestors.org, Apr 2008.