That's the argument Chicago is making. According to Chicago the ban is still in effect. The NRA is arguing that the ban has been pre-empted. It hasn't gone to court and probably won't go to court until the perfect case can be made and someone getting arrested becomes the perfect plaintiff.
So for right now I am advising my students to err on the side of caution and assume the ban is still in effect unless you want to be the test case and can afford to win. Like everything else in Illinois, the Judges will decide.