When Tracie comes home to watch the Corny Collins show, she smacks the television and says "Philco" while the TV is actually a Muntz brand.
Posters for musical events advertise shows on Friday, October 4 and Saturday, April 20. The story is taking place in June of 1962, but those two show dates only work for the years 1957 and 1963. The latter poster is seen on an outdoor telephone pole -- an unlikely place to promote a show happening nine and a half months in the future, and an impossible place for anything posted in 1957 to still be there.
The microphones go out on several occasions and the actors cannot be heard.