No online sources show that Robert and Sarah were buried in Rockingham county New Hampshire although many say they died there.
No Barbers are found in the cemeteries in Rockingham county.
Some sources say they died in Worcester county Massachusetts.
A Robert Barber and a Sarah Barber are found in the old common burial ground in Worcester county cemetery.
Their birth and death years are quite close to the various sources for this couple. See these liknks:
https://www.ancestry.com/imageviewer/collections/2495/images/40143_..., see No.112 and No.113
https://www.findagrave.com/memorial/79421959/robert-barber
https://www.findagrave.com/memorial/79593949/barb
