That depends if they started it from seed or bought the tree from a nursery.
Once a tree has been "containerized" it's best to trim the coiled taproot and let fibrous feeder roots form that can help to anchor the tree. If you're in an area where hurricanes occur, it's a good idea to try to root graft, so the tree has a natural taproot.
To root graft, you plan a seed near a surface root, then graft the seedling to the surface root.
With this method you can add a taproot(s) to a containerized tree planted in the ground.
Generally speaking a smaller tree tends to do better in the long run if it has not been containerized, but the best method of all is to plant a seed in place, and graft it when large enough. Easy enough to do with a potted plant by approach grafting.