Ad says the guy sold the car in the 80s, so apparently he did own it at one point.

I am all for the give it to the owner idea. If I had a broadcast sheet for someone, I'd be excited to give it to them.

I'm not opposed to selling it to the owner, as the owner clearly benefits financially if he has the broadcast sheet for his Superbird. If he wants it badly enough, he'll be willing to pay for it. $10k? That price is ridiculous, and the current owner of the broadcast sheet will have it until he's dead. I have no idea what a reasonable price would be.