During the opening sequence, McGee gets attacked by the German Shepherd. This results in him sustaining injuries to his neck and hand. In the first cut to the bullpen, there is no evidence of any injuries visible on either his neck or his hand.
When DiNozzo opens Abby's email, the summary screen lists the subject in all caps, but the opened message has the subject in mixed case. Additionally, the "From" space in the opened message is blank, instead of having Abby's email address and/or name.
Where the gang watch a plasma monitor to examine data about several members of a flight crew, the images show two Navy lieutenants in short-sleeve khaki shirts; however, the rank insignia on the collars are of a wrong type and wrong size - they're of the sort worn on the shoulder straps of raincoats - and they're incorrectly placed and oriented.
The bite force of a German Shepherd Dog is in the vicinity of 2000 Newtons of force, easily able to crush bone when angered. McGee would not be able to use his arm properly mere hours after being mauled, and would very likely be in a cast with a serious break. However, it is conceivable that Butch/Jethro may not have bitten him with full force as he is not an attack dog and only bit McGee after being startled while grieving the death of his handler.