The current make-up of SCOTUS would not throw out '86 or GCA. They've had a couple of chances on the '86 ban and a whole bunch of 'em on GCA '68 over the years. Besides, 1 little case in 1 circuit isn't gonna make it to consideration by them.
I think the best case scenario is rolling back '86 and a few other things through congress and redefining the scope of ATF.