I believe these are for deluxe seat belt(C15 on the option code or broadcast sheet) equipped cars only, and of course only for 1970 cars, that was the only year these were available. It is a pitty that the accuracy of the 23-49 section of the parts book has so many errors in it. There would also be a non-deluxe set as well, but I don't know what the seven digit number would be. The vast majority of 70 cars were non deluxe equipped seat belted vehicles.
BTW, the design of the chrome ends and the buckle with rectangular push button are unique to the 1970 model year.
BE and A's reproduction of 1970 belts use the 71 style chrome end. I think that because of this, the original 70 Chrysler belts are worth a lot more!!