Between 14:30 and 14:50 there is a plane change, where three darts in dartboard changes their position.
(at around 4 mins) As Don is pulling evidence out of the evidence bag there is a model car in front of him with the rear, or "rumble", seat open or raised. It varies between open and closed in subsequent shots.
The darts Charlie had thrown at the dartboard change position after Amita walks into the room.