while looking through the game files i noticed that there are two separate versions of the weapon AAGun2Mk1, one for multiplayer and one for the campaign.
the version used in multiplayer and listed in the guide is the AA Flak Cannon, while the campaign version is the Cyclone Flak Turret.
if there's a technical reason why both can not be listed on the guide i understand, however these two weapons are not simply a name and model swap. They are entirely unique weapons with different stats and requiring different upgrades.