Johnny,
Your 1970 has a universal two sided key for the ignition, doors, trunk, and gas cap. The slot of the expensive chrome one is centered in the middle of the hub, not offset to one side.
Unfortunately, the Authentic Classic one has a separate key and will be different than your main key, and also incorrect for the Car. So, if you want to win at the Amelia Island concours event, you are going to have to spend the $385 to have the Mercedes Benz Classic Center get you one from Germany. If you give Tom Hanson your VIN number, he will match the lock to the rest of your car and give you two new keys as well. I did exactly that, and am happy to only have one key on my Benz Fob.
Good Luck.
Mike Mizesko