Ryan, the ignition key is not too much of a pain to get out.
For your Fintail 200 Diesel, the ignition switch is connected to the pull starter knob on the side as a whole assembly.
Had this on my 1966 Universal wagon.

There is a string of numbers stamped on the barrel of the ignition assembly. That's the key code you need.

Believe your key will be with 'Niemann' on it big square head key with the teeth on one side.

Walter