i worked with a guy who was an extra on the show once lol. he played a corner man. he said he had no lines but the camera sits on him for a second or two. i forget which episode now it was ages ago when i briefly worked with him.

i've also been working in the city or close to it in some capacity since 99 so i am quite sure i saw some of the actors but i had no clue about any of that stuff so it would have just been another random person i'd see out and about to me.