When the Visitors banners are seen hanging outside the Los Angeles medical centre and other locations their symbol is rotated 90 degrees left. Instead of the two dots appearing right and left of the line the appear above and below.
(At around 3:50) As Julie wakes Donovan to prepare for the mission, he checks the chamber of what appears to be a semiautomatic pistol and then places it in his shoulder holster. However, throughout the miniseries, Donovan only carries a Visitor laser pistol -- never a semiautomatic.
Before the big battle at the beginning of the show at the Production Facility a photographer is photographing the arriving VIPs but he is not looking through the viewfinder and the camera's lens cap is clearly still on.