You probably don't need to worry but...IF the tree is being collected from the wild, the roots, or what is left of them, should be packed in wet moss and sealed in plastic for shipping ...you do not want freshly collected roots to dry out...(I am sure if you are buying from a reputable seller this will be done) I personally would want it to be shipped asap after collecting. I would also not dilly-dally about getting potted up and secure in the pot...no wiggles as soon as you receive it.
One the other hand, if it coming from a growing bed or nursery situation it should be just fine!
I hope since you're carrying the risk of a newly collected tree that it saved you a bunch of money! If not, I might reconsider and look for something more established.
Keep it wet and good luck,
John