Bones and Bone Marrow

[LostLocke]

Correct. Sort of.
The biggest detail, you neglected to mention, is that the quantity in marrow is very small. Plus, those stem cells are not "potent". They have a limited range as to what they can become.

Bones are 'just bones', they don't come inside a sheath. If you mean the marrow inside the bone will regenerate, then yes, that is correct.
If you're saying that a bone will grow back if it's removed, science totally disagrees. A removed bone is gone, permanently. And a removed rib will not "regrow" into a human, it will just die. At even a rediculous best case scenerio, the rib will just grow more rib.

Rib bones do grow back if removed. It takes 2-3 months and will reattach to the spine and be as good as new once healed. If a persons face is destroyed in an accident, the surgeon will remove a rib to reconstruct the face. If they need more bone, in a few months they will remove the same rib which grows back. They will remove it as many times as is necessary. 
Google it.

I did.

"Bones do repair themselves to some extent. But they can’t regenerate or replace themselves fully for the same reason that we can’t grow ourselves a new lung or an extra eye."