[C#] Natives concerning mission complete?

[cp1dell 1,949]

 Now, I know there is a function to check if mission complete audio is playing.  Are there any other functions, or creative ways of checking if a mission has just been completed, and is there any way to check specifically what mission was completed?

 

I would imagine that such a function exists somewhere in the game considering that certain weapons and vehicle mods are only unlocked after specific missions, and that this function was still being used back when DLC weapons were being introduced to single player still.