When Walter authenticates Neal's forged painting and turns over the painting to read the inscription on its back, the inscription changes between shots.
At the beginning (about 35 seconds) Mozzie says "Grand Central Station!?". As is so often the case in film and television, people invariably mispronounce this great building. It"s "Grand Central Terminal"; not "Station".
At around 36:07, you can clearly see the line for a mic coming out of Bomer's shirt.