...Interesting that he won trophies at the Nationals without the vinyl top listed on the trim tag. Wonder what category?
At that price, I would definetely ask for the certification, ask what's happened with the car since (a la Daniel's questions); and maybe, PM Jerry. If you really are close on the bid and have the top bid, one would think he would be willing to dicker...
Obviously, I'd put the vinyl back on it for originality, but I'd also think about driving it the way it is for a while. As jl8dale says, it has a great "stance".
Keep us posted!