I'm not entirely convinced by that. My passenger side overhangs the rear arch by a good 5mm or so. Driver's side fits perfect.
It's a bit hard to see because of the dirt and crappy iPhone focusing, but it's clear the pass side is longer on my car.
Previous owners must have replaced the passenger side one at some point and used a 5 door one, or maybe a pattern one if such a thing exists?
Passenger side:
Driver's side:
