Yes, of course, there are different types which are selected automatically depending on the airplane weight.
Right now we have two models (a bigger one and a smaller one) with a Towbar, and one Towbar-less, and they all feature human drivers, plus the Wingwalker that stays on the Pushback when it arrives, then steps down, walk to the airplane and act on the gear locks, does all the wingwalking up to the final pushback position, then unlocks the gears, and return on the pushback which will then return to parking.
We are planning to add new pushback vehicles soon after release, to cover more airplane types, even GA planes, with those small hand-operated models.
GSX has been very difficult to create, because it was made right from the start to be very easy to expand with new models and behaviors.