This Colt LE6920 M4 OG Green Carbine would make an excellent base for a clone build. It has M4 Feed Ramps, T marks on top of the upper receiver, has “C” stamped markings with the Cerro Keyhole Forge marks, "C" MP marked 16" barrel, C marked BCG, and no QR code on the lower. This LE6920 was made prior to Colt's acquisition by CZ and has actual stamped roll marks instead of laser engraving. Magpul Furniture. Bayonet Lug. This would be ideal for a M4A1 Block I, Block II, Mk18, CQBR, or Mk12 SPR clone build.