They are now forbidden by law to mark the outside of the luggage. It used to be SOP until the 80s maybe. Of course, it wasn't their fault that so many guns were stolen.
You may wish to research how you packed fully-loaded magazines. My understanding is that they can only be loaded if they are in magazine carriers, and not loosely packed. Others seem to maintain that they can't be loaded at all. I will also say that it is a small issue, and if not packed within sight of the actual firearm, you will probably never need to worry about it, the same way that I have often traveled with more than 11 pounds of ammo. They don't even look to see if you have a lot or not as long as your bag makes weight.
Taking guns seems to still be an easy part of flying. Too bad the rest of it has brought the industry to where many of us won't do it anymore.