The LE6920SCMCK was a retail upper receiver assembly.

“This Colt SOCOM Flat-Top upper assembly comes complete with charging handle, bolt and bolt carrier assembly. Featuring a Picatinny-style Flattop, this upper is more than ready to offer the shooter maximum versatility when it comes to mounting optic devices.  The quad rail handguard offers numerous mounting options for lights, lasers, and other accessories.”

Listed Product Details:

Caliber: 5.56 x 45 NATO
Material: Aluminum 
    (Dry film lubricated upper)
Barrel Length: 16 inches 
    (Heavy Profile Under The Handguards)
Rifling: 1/7 inches
Threading: 1/2" - 28
Sights: Yes Removable Carry Handle
Barrel Finish: Black Parkerized
Barrel Chrome Lined: Yes
Gas Block Diameter: 0.75
Gas System Length: Carbine
M4 Feed Ramps: Yes
Upper Receiver Type: A3 Flat-Top
Barrel Material: Chrome Moly Vanadium Steel
Bolt: MPI Marked
Handguard: Knights Armament M4 Rail Adapter 
    Assembly (RAS)
Bolt Carrier Assembly: Yes (Auto Profile)
Muzzle Device: A2 Flash Hider
Mil-Spec or Commercial Dimensions: Mil-Spec

Set included:
1 ea. "shoot through" plastic barrel cap
1 ea. .250" conversion pin for older 
    "large hole" Colt lower receivers
1 ea. Colt factory blue box

Product was discontinued either late 2018 or early 2019. 
Last listed retail price was $779.99.