value of (almost rolling) chassis BO29

It sounds like there needs to be some serious detective work done. Relying on "my friend said" is a disaster waiting to happen. If the BO29 car was parted out years back, it will be almost impossible to recover the parts. If the asking price is 60k to 70k, you will have more money in it than you will ever recover. Personally, I'd let it rest in peace.