Greg, I'm wondering if technically it wouldn't have to comply. My only guess would be that 314.25 refers specifically to covers and canopies, so don't know if the back plate of a wall mount fixture would actually be considered a canopy or cover in itself. I don't think I've ever even seen a listed wall mount fixture for any type of location with the factory installed non-combustible insulation like you see on ceiling mount fixtures that have an actual canopy per say.
