Equipment Exchange

I would consider the upper "near clone" since it has a shaved FSB.

Upper is Colt M4 -- C stamped with Square forge mark
BCG is C engraved -- CMP Bolt -- CE marked extractor
Barrel is 01/19 and cage code marked heavy (SOCOM) profile barrel with the smaller gas port (about .069 - .070). Shaved and re-parkerized original FSB.
Rail is early Giessele MK4 with the shorter front lower picatinny rail. Has a few blemishes from existing.

Overall very good used shape.

$1100 to your door

I would sell just barrel, gas tube, and hand guard $600 shipped.
Comes with barrel nut wrench and allen keys.