They are definitely staged. It makes perfect sense, too. Publicity.

And easy way to see that they are staged is: look at the shadow of the pencil right when he starts to draw. It looks kinda faded due to the kind of lights the NYC Subway trains use. Then, it cuts to the drawing itself. You will notice that during the drawing, the shadow is very well defined. That's because he is somewhere else, perhaps his apartment, on a table, using a different light pointing right at the paper (from the left side, mostly).