Buildsheet location?

Every mopar I've had has had the buildsheet in the rear seat back. Well, I bought my 1973 Dart Sport 340 as a basket case, missing the buckets, console, and lower portion of the rear seat. The upper portion along with all of the fold down parts were still there, and in nice shape. No marks on the screws, etc from any previous removal that I could see. Once I took the back off the seat...no build sheet. I have checked other places I have heard about, like fuel tank and glove box, can't find it. Where did they put them on Dart Sports equipped with the fold down rear seat?