Colt marketed two versions of the LE6920 SOCOM (SCM) Conversion Kit (CK). The two versions had identical upper receivers, bolt carrier assemblies, charging handles, barrels and front sights. Each version had different rear sights (carry handle vs. Matech) and rail systems (Troy vs. KAC M4 RAS). See additional sub-sections here for additional details and photos. As of the date of this entry (17 FEB 2019) both conversion kits have been discontinued and are only available on the secondary market.

Colt LE6920SCMCK with Removable Carry Handle and KAC M4 RAS
Colt LE6920SCMCK with Matech Rear Sight and Troy Quad Rail