There is no reason to avoid using real locations in a spec pilot, particularly if it is set in a generally recognizable city. Keep in mind the possibility that a reader may not recognize that specific location, so include details that will give a sense of the place as well. If that kind of specificity is helpful to the story, go for it.
When writing a spec episode for an existing show on television, it may be helpful to include the settings that are already established. When possible, reading an existing script of the series for which the spec is written is useful. It may help guide the formatting style, assist with structure, and reveal what recurring locations are labeled by the show.