Is that the same scene or situation where we saw the guy who played Vito as a customer?
When they shot the goodfellas scene Moltosanti cut his hand on the glass. They took him to the ER, still dressed up, and he had the blood from the scene all over his chest. When he walked in they threw him on the cart and started to rip his shirt off. "Take it easy, I'm an actor, it's just my hand This other stuff is fake". At least that's the story he told on the Talking Sopranos podcast.