Link to the page on HH;
http://www.hamtramck-historical.com/images/dealerships/colorAndTrim/1971/71_Valiant_Duster0006.jpg
(No need to steal the image to post - it is available at the source if you link to it)
The X9 indicates black for the color.
Even though the interior code is the same for the 4-door sedan, the sedan seat will not interchange into a 2-door, so be aware of that in your search.