Nice car!
The interior is called ''Boca Raton'' and the exterior color is called Silver Cloud.
Some people thought it was a love it or hate it look for these cars.
In a well preserved car like yours, it looks great to me!
As previously mentioned by gdrill in post #3, when the car is faded and the interior is in so so shape like his, it's hard to see the beauty of the package that these ''Silver Dusters'' have.
Actually, he has the car stored at my place for now and i have looked at it several times.
Again, it's a love it or hate it look just like many of the A-Bodies of the '75 - '76 years when Chrysler tried to make them more luxurious and fancy to attract new buyers.
Here's the page that shows the interior from the link posted by Vs29H1B in the Hamtramck Registry.
It was found in the '76 section, but late build '75s had this option available as well. (Obviously)
I hope this helps you..............
http://www.hamtramck-historical.com/images/dealerships/colorAndTrim/1976/76_Valiant_Duster_0006.jpg