It references Colt only. Pre '89 guns came with green labels. These "green label" ARs had bayonet lugs and flash suppressors. In 1989, California banned AR15s and a host of others from initial sale. This was done at the same time Daddy Bush's '89 import ban was enacted at the federal level. California's legislation listed the guns by name and not by mechanical features. Colt simply changed the name of the guns from "AR-15" to something else, like "Lightweight Sporter". These guns are known as blue labels as per the new labeling scheme that the factory did at the time of the name change. These guns did hot have a bayonet lug, but did have a flash suppressor. These are still preban guns and you can put any preban upper on them you want. Colt simply chose not to put a lug on them, it was not law. Then came the '94 ban which closed the door even further. Colt changed the name of the guns again to something like "Match Target". Nobody uses a label color to designate these post '94 guns.
To summarize, "Green" or "Blue" label are slang terms used to designate the era of Colt production.
Green-production start through 1989
Blue-1989-1994
XXXX- 1994-current
I'm not an expert in this field, so some of the above data may be wrong in minor detail, but I believe it to be a good overview.