As far as BC2 AA, I don't know, I didn't start flying until BF3 and wasn't that into BC2 in general because I had nobody to play it with at the time. I really would be surprised if there was an AA turret that could easily tip over every heli on almost every single heli map in BC2 considering how ridiculous that is.
Well, be surprised then, because it's *exactly the same*. Both the VADS(similar to BF3 AA) and the other one(not sure of the name, but it fires in bursts and the rounds are "larger) can both knock down friendly helicopters in exactly the same way. It's not necessarily every single map, because there are some maps where only one side got a helicopter so it wouldn't make sense to have friendly AA, but this is the case in BF3 as well if you include Rush maps.