Lemur, you also have the option to have either a black (correct) or white package tray to finish off the white interior. I too am going with a white interior for my '73, but I'm still unsure if I want it to look correct or try the all white (minus carpet) interior.
Have you decided if you're going to be doing a paint job on the car? I'm just curious what exterior color you plan on going with because while white interiors look great on all E-bodies, I feel Plum Crazy, Hemi Orange, and Citron Yella (and the Plymouth counter-part names) all look the coolest.
Here's a '70 that I'd like to make my '73 look similar to with the color scheme.