The sheathes will be fine in the safe Bruce. I have stored mine for years. No issues and no mix up on the sheathes. I also like to look at them together.

I do no use a golden rod since I have ivory knives in the safe but I would bet the slow convection would move air through the whole safe.

Keep an eye on the wood finish to make sure it does not discolor the back of the sheath. My shelves are lined with vinyl material. Just a thought.