Interesting. Prompted ai on the lore. It seems like it depends what you want to believe. I choose to believe that prior to later adaptations. In the original history, he always had healing powers along with the adamantium body, so the answer would be the lore never had any background on it. Later, it was shown that, yes, the claws were part of his bones, and if he could grow claws, then he could also grow bones.