In the latest episode of 30 Rock was that the actual doo-wop that is always singing in the NY subways?

I’m form NY and I remember seeing the same doo-wop group come through the train several times. They would always say something like “we’re not homeless and begging we’re just trying to keep doo-wop alive.”

In the latest episode of 30 Rock, Jack sings with a subway doo-wop group. Is it them in the show. Has anyone seen them enough to be able to recognize them or has heard something about them bringing in the actual guys.