[Latitude 28]

Take a look at my lock assy in the attached picture.  The brass internal pin guide on mine is the same as yours and will not need to be spanner wrenched off.  A technical tap with a brass drift pin punch on the pointed end of the pin with the lock in a vise should get you apart.  There may be an oring rolled and binding between the brass guide and lock casing. The difference comes into play with the magnet on the end of the, in my case long plastic piece.  Yours being shorter does the same function as far as the logic board.