diffeence between silk premium and photo paper premium

The premium product would have shipped second.

I recently ordered 2 indentical books....except one was the photo paper and the other was silk finishing (the most expensive option).
I received the first one 8 days ago...and the other one I received today.
order # is VV-67238-1 for today.

Question: How do i know for sure which one is which??? (I think I know but I want to make sure ) because i want to reorder my favorite finishing.

Can you help me???