Wow, man... IF that's not an original,then it's a pretty damn good recreation of a 1967~1969 XM16E1 rifle, in 5.56 NATO. No brass deflector, no fence around the mag release...
If you really want to create THAT rifle in .308 Win, then you need to do some machining to get it exact. Like, machining off parts of current-production receivers that are available. Also, I doubt you'll find a current .308AR upper that has the forward assist, and doesn't have a brass deflector (which could be machined off...).
How serious is this project?