Its dirty and loose... Sounds like we could get along. LAWL. Seriously though, its a battle rifle. I hope your going to put it though its paces. If you purchased to put on a shelf then sure, send it back. If you picked it up to shoot it. Take into bush, run and gun, use in anyway.... It will get dirty and maybe even a safe kiss... scary things for a rifle proven in battlefields to have to be put through. Screws get loose. Carry a multi tool... If you don't ever need to remove that screw, loktite. Problem solved... Even a mid loktite on ones you do plan on taking out cant hurt and will help. Id say take apart, clean. Anything broken or damaged. Send back. It could be a display model... Just look at the parts that move/slide if they have wear and arnt that nice pristine black... Maybe a bit of wearing to silver or something then yes its been used as display (people workin action) or shot.
100% would ask for new screws though.