Hey!
It's awesome that you're working on this!
That's not quite what we need to replace those parts, however. Since we're getting rid of the cross bar, the bottom part isn't necessary, and since we're plugging in a smooth rod, the nut isn't necessary.
See:
https://christopherolah.files.wordpress.com/2011/01/img_4534.jpg, except the smooth rod is not quite straight there.
Christopher