I’ve been offered a straight swap for my Mitsubishi Shogun against a 1982 Euro 380SL mechanically it’s excellent with 105,000 miles and MB history up to 96,000. Strangely it’s got all its old MOTs and bills but has had 10 owners

.
Excellent leather interior and mint hard top with a recently fitted original new hood.
However the body work could do with some work. Generally it’s very good with very solid underside and sills but one of the rear arches is badly rusted and the other is starting to bubble. Also has bubbling on the trunk and a small rust crack along the inside of the rear boot valance. Also has an AMG badge on it

(why do people do that?).
Do you think it’s worth the swap?
How big an issue is this single timing chain I keep reading about? How much would this cost to change to a duplex and how can you tell if it’s already been done?
Main dealer wants £1200 for the body panels, does anyone know of anywhere cheaper in the UK?
What MPG should I expect? I’m guessing around 18mpg, a little more on the run.
I'm having it tomorrow for the morning so I can take it to my bodyshop and general running around. Anything else I should be thinking about?
Anything else I should be thinking about?