If you revive the same teammate at least 15 times In Transit mode a green flash will appear from the revived teammate. This indicates that the perk has been permanently unlocked for use in Tranzit mode.
If you unlock the Gold camouflage for ALL weapons in a specific class (e.g. Assault Rifles, SMGs, Sniper Rifles, etc.) the Diamond camouflage for ALL weapons in that class will become unlocked for Multiplayer mode. For example, get the Gold camouflage for ALL Specials (Assault Shield, Ballistic Knife, Combat Knife, and Crossbow) to unlock the Diamond camouflage for ALL Special weapons.
When you complete Call of Duty: Black Ops II, be sure to watch through to the end of the credits. The developers have hidden away a humorous video there to reward people who see the full list of those who contributed to this epic game!