Are pickup trucks covered by this standard?
Not necessarily. If the driver can see directly behind the vehicle at ground level by looking through a rear view mirror, or by turning around and looking out the rear window, then the view is not considered obstructed and the requirements would not apply.
However, if the pickup truck has a load that would obstruct the view when backing up, or if work is being done after dark without proper lighting, or if windows/mirrors are damaged, or if severe weather affects the view, then the requirements would apply. If the pickup truck has a camper shell, it must have a front and rear window so that the driver can see when backing up.