If it's an '82 500SE it's a Euro for sure. Lots of the S class W126 Euro cars had cloth seats, but hardly ANY US spec cars had them, though technically you could order them. Mercedes believed that most US customers wanted the cars fully loaded and that they thought no Mercedes S was a Mercedes unless it had leather seats.
Often the Euro cars did not have tinted windshields, had skinny bumpers, Euro headlights (Glass H4), crank up windows, plastic hubcaps and dark plastic deflectors on the roof, cruise control stalk with German writing. Though some did have big US bumpers and US style lights after going through the gray market process. Take a look at
www.mbcoupes (special equipment) for side by side pictures of the different US and euro lights the W126 cars came with.
The Euro serial numbers began with WDB and the US spec ones began with WDBCA
A good one will, with its different axle ratio, less smog restrictions, and compression ratio, be damn near as quick as a US spec 560SEL.
Drive a 560 SEL then drive this one.
The 1-2 upshifts should be crisp, if the transmission flares theres there could be trouble. They are good and rugged transmissions and if they had regular fluid changes they could make it up to 250,000 miles without trouble. You didn't say how much mileage on it. As part of the gray market conversion process, usually the odometer and speedometer had to get swapped out for a MPH speedometer, and the German mileage added to it at the beginning for a correct mileage reading on the odometer. Was this done? ANy gray market paperwork to show the work was done to spec? Was there a plate or sticker on the door jamb with the Gray Market Import Import information for the car?
I'm quite sure it's a Euro car, gray market, though because the 500SE (The short wheelbase) only was sold in 380SE and 300SD iteration for 1982.
Another benefit of the 500SE is it's the hot set up in the short wheelbase so it'll handle and corner a little bit better than the SEL long wheelbase version.
Some people think (I'm one) the W126 SE looks more attractive than the SEL.
If it's in decent shape, runs out well, isn't rusty (if its a Northern or Midwest car it might be) or trashed and has most of the records, and if the timing chain, tensioner and guide rails were done, and the price is reasonable, it might be worth a real serious look.
General buyingguide tips for the W126 coupe most of which apply to the 500SE sedan can be found at
www.mbcoupes.com
Take that thing out for a test drive