I have a 73 Dart with a Metallic Parchment interior also. If you look very close you'll seen there are green tones in the dash pad and even in the carpet, as well as the painted surfaces. I had a local paint supply place match some paint for these surfaces, then sent a sample to Just Dashes where they mixed the dye to the same color.
I have all the information here some where if you need/want it on the colors I used for the dye, paint ,and carpet. Good luck!