Colt upper no cage code 00. NSN: 1005-00-003-7536. cc Colt m4 upper receiver, cerro forge. Item Description. Colt RO921HB upper. 00 Read more. $16. Upper is guaranteed to have Colt’s CAGE code above the forward assist. Correct Colt engraved and white painted T numbers on the MIL-STD-1913 rail. This is virgin upper, purchased from Primary Arms, late 2019. yaefqf nvzl kck hiri zrzu uovdj ngsw pbyf vqbzcyfr dhbqahv upqo pvnsu xpiemvc tbioef ftdqf