Some typical places were under the seats, in the springs under the seats, in the springs in the seatbacks, under the carpeting, and inside the door panels. There are others, so hopefully people will post up their experiences.
That's only the build sheet for the doors. There is a bigger build sheet that was usually hog ringed to the rear seat back. It's missing on 99% of the TR's built. Sometimes you get lucky and find one on the bottom of the front seats.
I didn't have a G-Body build sheet handy so I scanned this one from an 82 Toronado to give you an idea of what one should look like.
That's only the build sheet for the doors. There is a bigger build sheet that was usually hog ringed to the rear seat back. It's missing on 99% of the TR's built