I'm in about the same boat as you are. I just bought my grandfather's 1967 Skylark and i'd love to know where to find a build sheet and a window sticker... i just got started so i've got plenty of time to look. any info at all would be great!
Check some of the previous threads for ideas. But start with the easiest take out the back seat. I found some there on some cars. Also under front seats. UNDER CARPETS. Under sound deadener near heater core box, Inside windshield pillars. Under dash, inside door panels. And the holy grail may be above the gas tank if it is original. It is best to remove the tank and look as you could tear it reaching for it. After all the searching you may find nothing. But usually two types Fisher and Buick. Have fun.