Keen-eyed reader Lance spotted these photos on Wikipedia …

Vietnam People’s Army Marines

Vietnamse ready to perform their 1000th anniversary march (that would be the 1000th anniversary of Vietnam, not the Army)
They could be captured Colt Commando carbines, but given the condition that appear to be in, I think it is more likely that they have been purchasing Norinco CQ 5.56mm carbines.
[ Many thanks to Lance for emailing me the pics. ]
UPDATE: They may have been manufactured by this factory.