You will need to determine true birthplaces for both. 1855 Moriah Essex Co NY KNIGHTShow long in this city Royal 63 VT40y  Abigail 49 VT30  Henry22 b Essex Co22; 1837-1888 Agnes 14 Essex14 Sidney 28 Essex28; CW...9th VT Vol. Martha 22 or 27 Essex; d/inlaw Mary 10/12 Essex
1820 Essex Co Silas KNIGHT 120101-2111
1830 Moriah Twp;Silas KNIGHT and wife are 50-60 next door is Royal KNIGHT Silas and wife lvg 1840, but not 1850 If the info is correct for Abigail's name to be STANTON... 1830 Crown Point Twp STANTON: Alex., Amos b 1790, Edward 1782, Elisha 1783, James 1786....all b NY [per 1850]
I have no idea if yours VT BIRTHS Silas KNIGHTS b 4-13-1772 Marlboro VT s/o Daniel/Lydia; they also had son Royal b 12-30-1779;Mary 5-12-1777; Daniel 7-6-1774, and a couple of daus who died as toddlers. Royal seems to be a very popular name in the KNIGHT families, no matter where they are located, so a bit difficult to get a handle on it.
You might check with the Essex Co NY court for marriage of Royal/Abigail.Early vital records are hard to come by in NY.