Yes, I have had quite a bit of success with one (two, actually).
The one I use the most is the right one, though the left one works equally well.
The right gets used the most because I am a right-handed shooter, and when I am ready to take a shot, and need to squeak, the right one is right there, next to my lips.
I am, of course, referring to using the back of my hand(s) to make the squeaky sound.