I guess you could leave it in there to rot, but I wouldn't. After all, let's face it, our Buicks are not likely to become as valuable as the ridiculously priced hemis are.Add it, with your title and other receipts,to the info about the car.
Not only did I find mine in the driver's side door panel, I also had one from the upper rear seat cushion. Both mint shape. I took them both and framed each one of them in a nice picture frame...hung them both on the wall downstairs in my office next to the picture I have of my '87 Grand National. Away from sunlight. You should take real good care of these buildsheets, they are very valuable information about your Grand National. They show assembly line sequence, the date, model, body number, line number, and what options came with your car as well as the interior treatment. A real asset if you have to sell your car and these help back up originality of it. They also contain the VIN. Valuable documentation. You know the Turbo Regals and Grand Nationals are now much sought after high performance collector cars. :biggrin: These build sheets should be a valuable part of your documentation.
I kind of agree to a point. The one in the door is only the door build sheet. Not the total car build. The big problem is that the total build sheets are so rare in the Pontiac built cars so if you do have one consider yourself lucky. I doubt they add anything to the value of a car. We aren't talking Corvette or LS6 Chevelles here. Everything you ever wanted to know is on the SPID label in the trunk. And everything can be duplicated,even the build sheet so thats why I'm saying it doesn't add anything to the cars value. I've got every single build sheet for my Riviera T-Types. I dont think any future buyer really cares if it has power mirrors or astroroof. Those can be added(albeit expensively) after the fact. And like the TR they have a distinct VIN so it would be rather hard to sell a bogus car. As long as you have a cowl tag and the SPID label than thats all you need for documentation. Stash the paper away only because you have it and it should be preserved as back up documentation.
Another reason I dont put any faith in the build sheets is that they are really a printed cypher. Nothing but a lot of codes. If you dont have the complete listing on codes than what is the real worth of it? To check the options on the bottom half? The SPID label tells you that and more. The TR is a content specific vehicle. Other than options they are all the same. Same brakes,same motor tranny and axle,etc. Dont tell me you actually checked all of the little tags on the car to make sure they matched the little box on the build sheet?