Early in the run, "Buddy, Beware" was replaced by a reprise of "I Get a Kick Out of You" early in the run. This seems to have been done because Ethel Merman felt that if audience members arrived late, they'd miss the latter song, which originally was sung only in the opening scene.
Some online sources state that the production played its final performance at the Alvin Theatre on September 23, 1935, and re-opened at the 46th Street Theatre on September 30, but this is incorrect, at least as indicated by the daily ABC listings in the New York Times. Those listings indicate that the production played at the Alvin until September 28, with the listing on that date stating that there would be matinee and evening performances that day.
Vivian Vance was Ethel Merman's understudy for at least part of the run. Vance seems to have gone on for Merman at least four times, according to a report in the theatre column of the New York Times on Saturday, April 27, 1935. Merman had performed that past Thursday (April 25) with a high fever. Vance went on for Merman twice on Friday, April 26, a day on which there was a special matinee in addition to the usual evening performance, and the column stated that it was expected that Vance would play both performances on that day (April 27). Merman was expected back on Monday.
Although some books and internet sources list 420 as the performance total, with The Best Plays of 1935-1936 seeming to be the likely initial source for that total, that number is almost surely incorrect. At the time, The Billboard (then a leading source for theatrical information) listed 415 as of the closing performance, and that seems to be correct.