looking for a 535 to buy (Allgemein)

hi marco.
im not looking for a show car.
iknow about the e28 rust points,the damaged paint is good for me tax wise.
just looking for good base to work on.new paint and bodywork.
the vin say it had underbody protcion.
i more worried about the papers.how can i know the history of the car without papers.i also asked if anybody really seen the car in person.
regards
sagi.