DALLAS, TX (AP).- In Dealey Plaza, with the white “X” painted on the spot where President Kennedy was assassinated, ask anyone about the grassy knoll and the second gunman. Conspiracy theories come with the territory here. And at Barbec’s Restaurant on the other side of this sprawling city, six men sit on a covered porch and convene a meeting of the North Texans for 9/11 Truth group and talk about the government’s lies about 9/11. The group has 50 active members; 200 on the mailing list. And they number among many thousands who, after years of investigations, don’t believe the official version of how the World Trade Center collapsed, who was responsible or what the government knew and when. Politics doesn’t have anything to do with it; two were