Tillie,
Broadcast sheets for LA built cars are quite rare, but every so often someone does get lucky. Most of the LA sheets I have heard of so far were found under the front seat or seats tucked in the springs.
The other places to look are;
Taped to the back side / top of the glove box insert.
Inside the bucket seat backs
Under the rear seat bottom
In the rear seat back.
Under the package tray(speaker shelf)
Under the carpet
Best of luck! Look in all these places even if you find a sheet right away, there can be more than one.
My best guess is that someone had the rear windo changed for better visibility while towing as well.
Take a look at the passenger side of your engine down low, look for an aluminum tag with blue printing, it the engine is a warranty replacement the warranty tag may still be there?
Barry