When Greg is introduced to Wes Parker by his father, Mike describes Parker as a "golden glove" winner. Parker was actually the recipient of a Rawlings Gold Glove award. The Golden Gloves is an amateur boxing award.
When Greg asks Peter to see if there is any hair on his face, he moves upstage because he says the light was better. It was actually dimmer.
Miss O'Hara mentions that her "boyfriend" is parking the car, but Mr. Brady consistently refers to him as her fiancé. There's no obvious way Mr. Brady would know this detail about their relationship.