I'm not sure what you are proposing. Are you saying you want to cut out the section of the newer bumper skin and graft in the entire center section from the earlier skin? Well, yeah, anything is possible, but making it look good is another thing altogether. There is the plastic welding method using hot wires to melt into the plastic and hold pieces together, but then you still have to fill the gap at the seam and finish it somehow. If I recall correctly, that little aluminum piece has studs and a couple of nuts attaching it to the bumper skin. As suggested, you can probably just drill a couple holes and stick it on your current bumper.
Brett