Why do you need a proof that I purchased BitBox?
Do you suspect that it is not true?
But what profit can I get from lie about this?
Let's say that I have a hunch, and I learned to be very suspicious in forum.
I honestly suspect you didn't purchase BitBox hardware wallet, but you could easily prove me wrong with a simple picture like I suggested.

You could even make a small review and impressions about your alleged hardware wallet, so this can even be beneficial for you in the end.