Lithium-ion rechargeable battery, shelf life
Yes, Lithium-ion bateries degrades over time, even if unused. It is due to a chemical/physical reaction that starts right after manufacturing of the cells.

I can't answer on the state of your batteries. Because it highly depends on the storage temperature and also the charging level of the cells during the storage.

I don't remember the optimal number, and if you know it, don't hesitate to modify my answer, but AFAIK it was around 60%. Thus if you want to reduce the aging effect, you should store your cells at 60% charge.
I don't remember the optimal value for the temp.