A friend stated they bought 16 crates, each crate can contain 1 of 8 unique boxes. He opened the crates and received exactly 2 of each unique box.

2x box 1

2x box 2

2x box 3

2x box 4

2x box 5

2x box 6

2x box 7

2x box 8

I found that odd since the unique boxes in the crates were random. It seemed to suggest a pattern not randomness. I explained he could have received all of the same box, or none of the same box, or any mix in between.

What is the probability of receiving the above set of unique boxes from only 16 crates?