This is also the first cornerstone I have run across with Von Nerta as the supervising engineer. Most of them have been Neal A. Melick, who also worked with Simon during the latter half of the 30s and in 1940. In fact, this post office may be one of the earliest ones I have seen from this period, though I would have to check them all in order to confirm that speculation.
Like many other post offices during this decade, it retains the original wooden entry vestibule. Anyone who has lived through a blustery winter and spring in Texas appreciates the gesture.