Each and every model can’t be spoken for you here but most of the time, the tires should come inflated beforehand. Then again, do remember that the type of tire does play a role. Those that are not pneumatic will never need to be inflated and thus, this question becomes irrelevant. However, it can’t be guaranteed that every seller in the world will ship you the model with a pre-inflated tire.
If they do not, the manufacturer should have the recommended PSI of their tires somewhere in the manual. If you can’t find it in the manual, you are sure to find it on their website or the official product page for your specific model.