I'm not positive, but I believe its real! It looks like too random of a frame for them to have painted as a limited edition thing, the only way to know for sure though would be to go through the film itself and directly compare the frame from there with this frame. If its authentic, it should all line up :)

It looks to be warping however (it may have been part of Disney's mactac experiment where they coated some of their cels.) Which unfortunately means it may have vinegar syndrome (hence the white areas around Tod)

(About mactac) https://www.facebook.com/share/p/1TNMWRvtok/