Never mind, pretty sure I figured it out. Part on the right is thick enough that the seal flange will clear the parking brake hardware without cutting it.
End of edit.
That didn't take long - next question!!!
In the attached picture, I think I need to trim the flange that holds the bearing seal to match the plasma cut piece that came with the brakes. And that just goes over the top of the cut piece and you dress that sandwich with silicone gasket sealant.
Thanks again for getting me over the first hurdle.
Derrick