Looking for info on dining room ensemble

Over the past weekend, our non-profit organization received a donation of the dining room furniture seen here -- a table with leaves, six chairs, and a sideboard. We do know that these pieces were actually in the house, as the person who donated them had purchased them at auction there several years ago.

The sideboard was actually trimmed to fit in the very niche in which it now again sits.

The house dates from 1902-1903, and while we suspect the furniture may not have been the first set in the house, we are wondering about its possible vintage and style. Any information would be hugely appreciated!