If the chain jumped, you will probably need new valves on one or both sides, and there is no way of telling what is going on with the injection, electronics, climate control, and transmission.
It is really a matter of luck - you could very easily end up 'way over market value. Or you might end up with $300 for the chain conversion, and $500 for the heads and have a great car on the cheap.
Look at the cams carefully before you buy it.
Do a search on 'wayward woman' to learn about my experience with a similar situation.
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe