He's probably right about the fuel pump needing to be rebuilt. Kits are available. Not a big deal.
It sounds to me as though he has a Demonstrator model from 1975 or 1976. Case sold these at a special price to the dealers. They have a large black decal in the middle of the hood and if the rest is still there, the word Demonstrator along with black pin striping will be on the sides of the hood.
Original examples are quite collectable so don't alter anything on it if you end up with it or you will ruin the value of it.
Feel free to send me an e-mail if you need further information.