Most of the UPS Store locations will tell you that it's illegal to ship a gun, period. With anyone. Ever. Don't ask me how I know.
It's the same with Fed Ex. If you go to the Fed Ex Kinko's, they're just as clueless. I was shipping an old 1903 stock at the UPS store and everything was going fine until the guy behind the counter realized what I was shipping. Because of the size of the box I was using, he wanted to make sure it wasn't a rifle or something like that. Instead of saying "No, it's a piece of wood", I told him it was a gun stock. He about had a coronary right there. He told me that UPS doesn't ship anything gun related as a matter of policy and started to berate me for trying to be dishonest.
I've since just started going directly to the hubs if I need to ship anything. Even the people working at the UPS and Fed Ex hubs are amazed by the cluelessness of the retail store minions.
Matt