This is about as authentic as you can get for Hong Kong style noodles and rice dishes. Just take a look! Most of the customers are Asian; most of the wait staff is Asian and of course the 4 chefs/cooks are Asian.
Yes, it costs more since it is in the Venetian but by the time you get in a cab or drive to Chinatown, you have wasted precious time away from strip.
I recommend any of the noodle or rice dishes - big dishes too. What is more impressive is the dim sum. They have it ready to steam and it comes out fresh.
And the additional bonus - cleaner than those chinatown establishments.