How is "stealh" defined here ? Not alerting the humans of their presence ? If so, then it's not much of a stealth chopper, as that dude that blogged/tweeted about the whole thing had heard it.
Actually the neighbours reported that they didn't hear the helicopter untill it was right above them. which as far as helicopters go si pretty damn stealthy on the sound front. especially for something int he size class (and probably built off of) of a BlackHawk.
But since it was used to enter another country without asking first, Radar stealth is probably more important in the big picture.