I predict they will claim that since extended magazines exist, the ability to accept detachable mags makes them non-sporting (see the bit where they gripe about rifles with extended mags being 'unsporting')
Then expect the grabbers to follow up with a "why do you need an "unsporting gun?" and try to ban them domestically.
The best bet might be to bitch like mad with a fallback that there should need to be two or three items on the list to count, not just one-- ATF is reasonably happy since they can claim to be doing work and defining eeeevil features while shooters are reasonably happ