According to the Taibi book I am looking at Stockbridge's depot burned to the ground in 1888 and the replacement was a 7x9 foot shed, sold off in 1942.
However the NYO&W had three depots in the town of Stockbridge, Munnsville and Valley Mills being the others. The latter would also burn to the ground in 1893 and be replaced first with a similar 7x9 shed, then later a pair of a very plain 12x16 structures that had no real railroad appearance at all, one serving as a freight house. The photo of the latter shows it had two relatively large square end windows, a peaked roof, and a door about 2/3rds the way down the building.
You may have to go back to the tax maps and look for something with 12x16 dimensions. I see nothing that might match up save a swaybacked tin roofed thing in front of a barn that is half round topped a bit east of where the link above takes you, that seems to be only in the Bing street view and missing in the satellite images. 12x16 would be the size of a one car garage, provided you didn't have a '59 Lincoln or something.