Yes, the 7409 is the correct sweep. The newer "H" style sweep does not have the slots for the bar and it connects in the leg sockets on the bottom of the bowl rather than to the sweep assembly. The 7409 comes with everything you need to re-attach the ash catcher ring.
To remove the old, just remove the handle (there is a thumb screw at the bottom that will allow it to come out) and if that breaks (common), just dremel it out so it is flush with the nut and the assembly will fall out.
Hope that helps..