Build sheets could be anywhere in your car. LA was well known for placing them on the fuel tanks. Not every car left the assembly line with one. some cars have been found with sheets from other cars, some with two build sheets, It was simply a way of disposing of left over trash. They have been found in the front seat backs, stuffed in the seat springs, under the carpet, console, stuffed under the dash, on top of the glove box, It could be any place. Dont get your hopes up on finding one and tear your car apart, chances are you wont find one. I have had a few very low milliage original cars and never found anything, but had fun looking. Good luck.