There’s an entire thread over at the TBBT wiki devoted to finding the exact spot the shot outside L&S’s apartment was taken from. (No link. Dude, you have better things to do with your time.)
TBBT geography is a hopeless mess. The address is well north of Colorado Blvd, but within a very short walking distance of a mythical gas station on it. But the zoom out at H&B’s wedding and the apartment view place it S of Colorado.
It’s like the entire show fell thru some sort of wormhole.
Note when watching a stairwell scene how the dialogue and laugh track blend together correctly. It’s magical how the “live” audience manages to get the timing right despite the set changes required to film the scene.