Of course they COULD. The question is "What are they LIKELY to do?". Seems to me like a couple of them are just looking for a valid excuse to tee-off on the second amendment. This could easily serve as the tool they have been looking for.
To be sure, GCA'68 also has some jurisdictional problems though with some slight work and state coopration the felony gun ban could be implemented in such a way as to pass even strict Constitutional muster (making use of the "full faith and credit" clause and the convicted-criminal exception to the Thirteenth Amendment).
I'm not so sure of that,but it doesn't really matter at this time. First,they have to hear and make a pro-freedom ruling on a "nuts and bolts" case like this one,and then we'll see what happens down the road. I personally don't see ANY justification for keeping a "convicted criminal exception" alive,but who knows how the knees will jerk on a panel of judges? No other group of people are more pre-disposed to find such a thing valid.