(at arouns 32 mins) Jimmy enters his office at the back of the beauty salon. He unlocks the door and has to push a chair out of the way so that he can open the door enough to fit through. This wouldn't be possible unless someone stayed in the office and pushed the chair up against the door after he locked it.
Abuelita's living room has an embroidered sign on the wall that says "The Hurrier I Go, The Behinder I Get", which is an odd choice of art for someone who speaks no English. A local home in Albuquerque was used for filming this episode and the simplest explanation is that the wall art belongs to the home's true owner.
When Tuco pulls Jimmy into the home in the previous episode, he takes a peek outside and turns to the right almost looking into the camera. When the scene is repeated in this episode Tuco just looks outside but does not turn to the right.
Although set in 2002, in this episode, Tuco (the eponymous "Mijo") threatens Jimmy/Saul with a Taurus Raging Judge chambered in .454 Casull revolver, which was not produced until 2010.
When Jimmy gets out of his car to get more stickers, a post-2007 Chevrolet Silverado can be seen parked in the background, when the scene is set in 2002.