Correct. IIRC Dan Shea (bought and sold LOTS of movie guns when they went anti-gun in the 90s in CA) sold one of those MAC 10s for 4-5k when the prices were were ~<$1k.
Had a good friend who was a class 3 dealer and brought a Mac11 out to my range. It would empty the entire mag in about 3 seconds. It would only eat Federal .380.