Did the mail go through?

photo by Ballard Avenue

Over on 30th Avenue is a relic of the past—a US Mail relay box. Ballard's letter carriers used to do their routes without vehicles. They'd walk or ride the bus to their route, and their mail would be stashed for them in green boxes like this located every few blocks along their routes. The boxes haven't been used in years and most were removed, but somehow this one survived. Are there any letters inside?