The question, I suppose, is where to draw the line. Obviously the street signs and lamp posts, buildings, parking lots, and so on are NOT props. Unless they are specifically and particularly made for use in a scene. All the tables in a real casino, the chips on them, the cards, dice, etc., are not props, unless they come into actual use by the actors. Obviously, if a casino set is created EVERYTHING in it is a prop. And props don't necessarily have to be handled by the actors to be props: I have supplied props -- flags (of course!) -- for the movies Born On the Fourth of July and Pancho Barnes, as well as for some local stage productions. These remained my property, and I was paid for their use; they appeared on screen, but were never handled. They were part of the period-correct background scenery.