I can confirm that a freshly opened box of single blind packs will have numbers in order... #1-4 across the back row from L-R, finishing with #21-24 across the front most row.
I was looking for #13 and grabbed the left most pack on the 3rd row back and sure enough it was Rootwing. The # is printed right-side up on the back of the pack, to the right of the opening tab. Not sure what the sideways printed codes are running along the side of the pack, but the number is all you need for ID of the figure inside.