I just bought a '75 Steel Blue Convertible and it came with no documentation.  I've had the tank checked with a camera and the Tank Sticker is gone.  

Hey Rick, I just did some work on a '75 a few months ago. Dropped the tank to replace the sending unit and fuel lines. On that car there was a separate metal shield between the tank and the body. The tank sticker for that car was in perfect condition and stuck to the outside of the shield not the tank itself. Check it out and good luck !!

Mine is a 76 and found mine in the same place (the shield between tank and body).  It was pretty much a goner from the elements though.  I assembled it best I could and took a picture of it, but mostly illegible (just legible enough to tell it was the build sheet).

I've red that some were found under the carpet under the driver's seat, and stuffed up between the speedometer and tachometer under the dash.

Me?, I don't have mine.

Thanks All!!!!  I'll keep your input in mind as I gradually go through the car.  

Build sheets can be found just about anywhere on the car. Most common location is of course on the fuel tank. They have been found under the rear carpeting, in the seat backs/bottoms, behind the dash(speedo/tach cluster), you name it. There have been several found between the rear strut rod bracket and the bottom of the differential(in some'78 cars, anyway). It's possible the sheet is gone, regardless of where it was originally put. For instance, in '74, there was a recall for a faulty vent tube on the fuel tank. If the car was repaired under warranty/recall, the sheet was destroyed in the process. But there might still be another one in the car somewhere...ya never know. I've had my '74 completely apart, and the only place I found any evidence of a build sheet was on the fuel tank...I could see where it used to be....