The front piece is definitely a bumper skin, and it's made to go around the bumpstops on the pre96 XJ bumper. I suppose it would be possible to retro these pieces onto a 97+ with some effort/ some parts off a pre96.
i like the look of the exhaust cutouts on the rear but not too sure if i like the front bumper too much.. dont think it would look that great with a license plate from the states