Hello peeps. I just got a brand new Ruger 556. This is my first AR. How do I know what model or whatever it is. It says Ruger 556. But when I go and look them up mine has a different forend, the guns never been shot maybe it's had the forend change and I don't have a front sight on the barrel. Idk diddley squat about Ar'S but I've always wanted one so I'm in this one for about 400$. Thanks for any help or information.