If you've flown a Hughes 500 you know that there's a spring that pulls the left pedal forward as the rotor slows. Sort of an "automatic" rotor brake.
MD 500 and 269/300 are similar in this regard. I have been taught that it is poor form in these machines to allow the pedals to sit hard over in either direction for any length of time. As the tail rotor blades are retained by blade straps, which are slightly streched at their edges during full deflection, full defection is to me kept to a minimum.
I have seen many techniques demonstrated after touchdown. I have always been most comfortable with the "attend the controls, and hold them in their sweet spot, until it stops" approach myself.