Value G 230 GE

Hello together A good friend of mine will soon separate himself from his 230 GE (1988/W460) completely original with guaranteed 79’000 kilometers. It is the short version with blocking diff back, etc. etc… There are bills about investments about Sfr. 21’000.–. The car has no rust. The car was presented fresh last year, in the meantime only about 2’500 km were driven. In addition, the 80’000 service was carried out. The car was never in the Gelän What would you pay for such a vehicle – which versions are long or long version?? Is it worth buying such a vehicle in terms of value increase? Thank you for your answers and greetings Beni