bill of sale matching numbers on frame and chassis

I have a 1970 pontiac lemans, I bought it a while back it has a salvage title but have separate bill of sale for the frame and chassis to reconstruct the title. The lower rear pass side quarter panel has some rust through there is a small 2x2 rust through in the passenger side floor. It has the dash half of the back seat the upper half but no other interior. So just a rolling chassis 10 bolt rear end.