The real steel CAR-15 was the precursor for all carbine models of the M16 family. The original CAR-15 actually only existed as a prototype, its later variants where adopted into the US Military in the late 1960s.
G&Ps replica does a good job in bringing this old timer back to life. Ut features the original shortened triangular handguard and spring stock like the original as well as the short type 11.5 inch outer barrel and three prong flash hider.
It even comes with the non-detachable carry handle like the old Marui M4s, no rail attach accessories here; the MIL-STD 1913 Picatinny accessory rail would not come into effect till some three decades later.
Despite the middle aged externals, the internals are up to spec G&P benchmark standard M4 internals. Clocking in at around 330 fps, feeding from a 110 round short type midcap magazine. The battery (not included) is front wired in the handguard and will thusly take a small type battery.
The earliest use of the CAR-15 was by US Navy SEAls in Vietnam around about 1962. If you want to do this replica justice, add it to a Vietnam SEALs loadout.