You’ll notice it has a SB Tactical® SB-A3 adjustable arm brace.
May be just me, but if some kind of ban or re-re-reversal from ATF regulating these a buttstocks on the radar, I think S&W wouldn’t be introducing a braced AR pistol right now. Of course, they may be subtly informing the bureaucraps that they intend to play hardball and to lay off with the BS.