My take in this is to create the registration framework NOW etc. then figure out how to force the rest of us onto it later, either after the SCOTUS is packed to their liking, or legislation can be passed, or they figure out creative ways to use Obamacare, VA benefits, FHA loans... You name it to compel people to provide the data...
The bright spot is that either our enemies are truly incompetent to advocate duplication of effort like this, or the ATF's 4473's from old out of business FFL's is FUBAR.