Hello again, Build sheet question

Does anyone know where the build sheets are normally found on a 1977 el camino?
I was told they are above the gas tank, but I dont wanna drop the gas tank if i dont have to. Any other spots it might be located?
Thanks!
~Phill~

I found mine ( 78 Elky )when I replaced the head liner. You might try their.

Some are in the seat.