I misread that that you're not removing the transom assembly from the boat.
If I am understanding him correctly, he is in fact removing the entire transom assembly from the boat.
gostephen: This is the part you are replacing, correct?
You are reusing your old parts including the inner transom plate and the "helmet" - correct?
You mention ordering the exhaust bellows, but do not mention the drive bellows. You are replacing that as well, right? You ought to go ahead and replace the shift cable and bellows while you are at it. Plus have a good look at the condition of the transom itself when you remove everything.