armrests and shoulder belts optinal on a 70 Duster?

I have a 70 duster with deluxe interior(per broadcast sheet) which looks more like a taxi cab interior to me and there are no rear arm rest, the rear trim panel build dates coincide the cars build dates and I have owned the car since 85 I don't believe any of the previous owner ever had the interior out of the car so who knows.:dontknow: