Contact MBUSA, they should be able to send you a copy of the original window sticker. I have done this on 3 different cars. My first Benz was 20 years old when I bought it, yet MB still on a copy of the window sticker on file and sent me a photo copy of it, for free.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member