In addition, there is a mod that cleans up even more than these two files do at Piper PA28R Arrow III (JustFlight) - Clean Interior » Microsoft Flight Simulator
You can use both together to (the included JF clean textures and the mod). The mod does clean things the JF texture doesn’t. The mod does not clean the windshield like the JF textures do. So it may be preferable to use both if you want a really clean interior.