G&P metal bodies come with all the pins you need, including the charging handle, but I can't recall if the mag release was included. Either way you can buy a mag release separately.
The charging handle is about 5 or 6 inches long, and it serves as its own guide moving along the top of the inside of the upper receiver, theres a spring thats attached to the upper receiver and hooked onto the charging handle. Other than looks it serves no real purpose on a G&P gun.
http://img.redwolfairsoft.com/upload...-M4-07-E_L.jpg
This is the breakdown of a CA M15A2 carbine, the only difference between this gun and the rifle is the front set which contains the same, but longer, parts, the inner barrel and a full cylinder in the gearbox.
http://www.classicarmy.com/catalogue/113_P7P7.jpg
Now it's not a VN but it'll give you a good idea of what goes in an armalite.