When Mrs. Whipple is leaving Granville's room with the morphine container, she is shown closing the lid as she walks through the room to the door. When it cuts to her from outside the room, the lid is wide open again when she is closing the door.
The son of Whipple's friend who died in the Civil War plays "Last Post" at Whipple's funeral. He would have played "Taps" and not the British/Austrailian call.
The bugler did not play Taps at the end. Taps was played at lights out during the American civil war, originally borrowed from the French. The music was changed in 1862. The tune does not fit the show's 1876 timeline.