Yes, Koichi did went to New York for the screening. It's actually a Private screening (so, no wonder we all heard the news, late :/)
First report from Wayne, who was one of the cast of the movie. You may also read the report + here + at D2 :)
Related news
The "Sushi Prince" goes to New York
The city was an appropriate choice for the screening, given that the film is set in The Big Apple. The PR campaign also took advantage of the link between the city's initials and one of Domoto's catchphrases in the movie, "nigitte yaru!" (translated as "I will crush you!").
At the event, Domoto introduced himself in English by saying "I'm Sushi Prince," which was greeted with a round of applause. When asked about a possible sequel, he seemed hopeful that the film gets turned into a series. However, the film still has not been given any formal release dates outside of Japan, where it opened on April 19.
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I decided, Koichi has separate tag xD