I read the study a while back. The bottom line is that the ATF study is about imported shotguns. It doesn't concern domestics. They're thinking about doing to shotguns what they did to assault rifles back in '89, i.e. if it's foreign it can't be too "military-like" but if it's domestic then the sky's the limit when it comes to all the imported no-nos such as bayonet lugs, hi-cap mags, flash supressors, etc.
Even if this study does become law (it's a long ways away from that) it'll be just like the assault rifle BS - buy the sanitized imported shotgun (it's mostly aimed at Saigas) and trick it out with all the aftermarket accessories that you want.
(Insert random tough-guy quote here)
"See my gun?? Aren't you impressed?" - Anonymous sheepdog
Guns - the alternative to running for your life.