Exposed rafter tails i.e. open cornices are very common, particularly in milder climates. The tails do not end flush with the wall, but continue out to form eaves. Obviously, the space between rafters is blocked. Maybe the previous siding installer took care of it, but the problem with adding a facia is that the roof deck often ends flush (or nearly so) with the end of the rafter, so you either have to install a very deep drip edge to cover the top of the facia board or trim back the tails.