The "factory" box stores the barrel and action seperately, much like an 870. It's easy to take it apart. Trust me a dis-assembled shotgun box looks way too short to be a rifle and way too long to look like a handgun. Hickory Farms, Macy's, etc have oodles of shipping boxes about the right size which will further confound the issue.
I know when I was gifted my Remington shotgun I had NO clue what was in a box that size.
The jewelry box with a shotgun shell in it is a great idea as well.