I Know,,,, I went through this with my sister a couple years ago, she's a post master in a mid sized sight. She argued up and down you couldn't till I pulled it up on her puter from the ATF and Post Office sights regs. Of course if you knew my sister you'd know she's a bit argumenitive most of the time anyhow!!! Our family is all a bit stubborn,,,, all but me of course!!!
I must addmit it took a bit of searching to find the info, it was well barried in a cluster fuck of sub sections, as usual. I think they just didn't want to take the time to look, they are stretched pretty thin now days, at least around here they are.