There's a nice close-up of a Baldwin piano and its clearly printed name during the 1840 opening scenes. However, the company didn't exist at that time. The Baldwin Company didn't make its first pianos for another 50 years.
The prologue is set in 1840, yet the house has electric lamps and air conditioning vents.
When Toby and Kevin are making love, the camera pulls back to show the shadow of the cameraman on the glass of the bay door.