Found a second buildsheet in my car??

Yep, it was in between the springs, the first one i found under the front bench which was really prettymuch ratfood. Any info on the codes? And where i can get the rear sail panels? This car has a cardboard like headliner, is this common in 70's a-bodies? I broke one of the rear pieces by accident and now am looking for a source on those. Could there be another bsheet in the headliner? I was very happy when finding it lol i felt like a little kid with candy.