One Ichabod or Two?

Ichabod Martin seemed like a fairly simple find.  NH records show him as born on 5 Mar 1759 in Weare, NH, to Nathaniel and Mercy Goff Martin.  He enlisted in 1776 in the 1st NH Regisment, for 3 years and served out his entire enlistment.  He married sometime around 1788 (no record found so far).  He lived at first in NH, then in Vermont, and finally in Cortland County, NY, where he died in 1810.

And then he filed for a Revolutionary war pension in 1829.

This rather throws the  above knowledge into disarray.  We can be sure that "our" Ichabod Martin died in 1810 in Cortland County because his son Bishop Martin, as administrator of his estate, reported the date and place of Ichabod's death and listed himself as his son.   In the 1850, 1860, and 1870 censuses, Bishop lists his own birthplace as Vermont, matching one of the records for Ichabod there.   The 1790 census for Ichabod lists himself (presumably, 1 male over 16), his probable wife, and 2 sons under 16, possibly Bishop and Ichabod.

It is apparent that Ichabod who served in the 1st NH regiment cannot in fact be Ichabod the father of Bishop, assuming that Bishop did not fake administering the estate.   But which Ichabod was the son of Nathaniel Martin and Mercy Goffe?   Which one appears in the Vermont Census?  And did 'our' Ichabod serve in the revolution or not?   Lots of questions to answer.