[tom406]

Take lots of good pictures of all of the things Jerry says are "COPO-esque" while the car is in its unrestored shape. As Stefano points out, once restored, all of these clues will be questioned. Its not paperwork, but if you show good evidence of how you found it and why you think its real, that may help convince people down the road.

I also agree with Stefano that it certainly isn't an either/or thing when it comes to bulletproof history. Many collectibles, cars included, have a value set by whether they're definately/probably/maybe/not what you think they are. I know I've paid more for something that was "probably" a Z/28 than I would have for something that definately was not. (I was rewarded with a build sheet on the tank for my guess.)