When Orson and Richard go to the dressing room to check on George Coulouris, as they turn the corner, Orson is in a suit. When we see them complete the turn in the next shot, Orson has on a black trench coat.
Richard accompanies Orson to 485 Madison Ave (CBS) for a "recording session" for a radio show ("The First Nighter" program). At this time (1937) and until the late 40s network programs were broadcast live, never recorded. Most programs were produced live twice, once for the East Coast and three hours later from the West Cost.
A common mistake in movies and TV, fire sprinklers are activated individually - a match held to one would only cause that particular sprinkler head to open, and not all of the sprinklers as shown in the movie.