Perhaps I misunderstood which part that you are looking for? It is the lowest outer piece right? Or is it the black piece that actually touches the radio?
I though it was the lowest, outer one like the ones in this picture. (These are for a 1970 Plymouth E-Body)
Now that you are asking about the a/c panel for Rallye dash I wonder....
You do know that the outer lower dash pieces fit either Rallye or non-Rallye dashes right?