I have not kept updated on this type of issue, but it used to be that assuming you had the original lock tumbler the Dealer could cut a new key for you using the VIN. However, some dealers were picking and wanted the registration and so on.

If the Mercedes classic car center is still around perhaps, they do the key cutting now.

There is a locking block on the lock tumbler and if the tumbler cannot be turned to the correct position the locking block will not disengage. To turn it to the correct position you need the key.

This has nothing to do with the key but when I thought I had a lock tumbler issue it turned out that the steering column lock was broken in 2 places, and I also found out one of the contacts on my ignition switch was badly burned.

If you are going to get the tumbler out, you might as well inspect the steering column lock and your ignition switch.

Again, not I am not updated on this. A few years ago, there was a shortage of replacement steering column lock assemblies. If you managed to get a new one, they come with a new ignition switch and a new vacuum switch. Be sure it comes come with those as buying them separately costs more.

__________________
84 300D, 82 Volvo 244Gl Diesel