When Saul goes into the HHM law office for the first time, he enters an elevator then and goes up to a floor. Once he gets off he goes up a flight of stairs to the conference room. The view from the conference room is on the ground level when he should be on the third floor at least.
Jimmy visits Chucks home. He deposits his 'phone and other electrical items in the mail box. This is foolishness. They could be stolen. It is more sensible to leave them in a locked car. Ditto following chapters in each series.
Vehicles that didn't exist in 2002 are visible when the twins are hanging onto the back of the truck while on their skateboards, such as a 4-door Jeep Wrangler.