1. Put a Chiseled Bookshelf, and put six books into it.
2. Use "Middle Button" key to get a copy of the block, and use "Ctrl + Middle Button" to get a copy of the block with NBTs. 
3. Put the two copies down. 

Observed: 

Two copies look the same.

Should be:

(After put one book into the second copy also look like this, and in Survival Mode, the book will missing)

After breaking the Chiseled Bookshelf (in Creative Mode) will let those books drop, even in the observed state.