Clearly I did not ask to see it first. Nothing registered to me as being "wrong" until he brought it out and I saw that it was already open. I'VE ALWAYS opened them myself in the past. I assume there's a good reason OTHER FFL's had me open the box myself... that way if there was something wrong/missing, it would be immediately clear that it was a factory or shipping error and not due to his actions.
A shipping refusal is way more preferable for both of us if I open the box and there's something immediately wrong. Him opening the box in the back room makes no sense to me, and introduces numerous potentially bad variables with zero benefit that I can see.