Yes, they would be hatchlings.

The main point with taking the risk on the normal balls is to learn first hand about the different problems I can encounter with snakes.

In short, I am questioning whether the experience I will gain with the "free" snakes will add significant value to my ability to care for more expensive balls.

Please note that I am not suggesting that the value of a free snake is any less than the value of an expensive snake. The only difference is the cost. I would treat a free snake the same way I would treat an expensive snake.