This is the first car I have seen it on. All the Serpent, mugen and Yokomo cars, etc all use setscrews to keep the hinge pins in place. Other than that the only other way I have seen on a Nitro car is e-clips.
However, if the rubber is tight enough it will hold the hinge pins in place. Serpent use rubber o-rings to hold the pulley on the front solid axle and their front one-way.