Jerry,
Any Randall ordered with a leather handle, i.e. a "full" leather handle, will have an exposed nut. The internal (flush)butt cap nuts are available on handles of any other material. It has to do with amount of pressure and torque needed to compress all of the leather washers, along with the fact that the exposed nut allows the handle to be re-tightened, should the allum escape or dry up from between the leather washers.
I have found a photo showing the "brass on brass" you were speaking of. Hope this helps.
Best, Capt. Chris