I have successfully ordered keys for both of mine by VIN.
Look at the size of the key slot. Sometimes they get changed to a generic type of lock, and the slot is thinner than the slot on the door. The MB key is wider than others. That might help to know if you have a chance with the vin.
Also, if you order he key, it does not work, then you order the tumbler you will have 2 keys for your car. and typically get a price break on the 2nd part.
I can not live with one key...

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83 300SD Dark Silver Dark brown inside