I had heard a similar date for the feed screws. The house that goes with the barn is a confirmed 1758, according to the owner. I believe they have researched it with the historical society, or possibly town records. This barn is in Canaan, NY.

As for the removed section, that is a bit of a mystery. The corresponding framework on the other side of the central bay has a post that runs to the upper tie beam. I'll be back in a minute with photos.