Do my case packs get some type of identifier sticker?

I have 1 small product with 4 variations (colors). I have packed up 140 of each color into 4 separate boxes and put those 4 boxes in a bigger box. But during the shipping process, I do not see any labels for the smaller containers.

How does Amazon know which product is in each of the 4 boxes? Are they just going to open up the boxes and check the fnsku on the products? or am I missing something?