Yes, the top photo does look like a howitzer is placed to defend the house but scroll down for a little broader perspective. I attended a ceremony at Ft Huachuca and took this photo on the parade grounds. "Colonel Row" is the nickname for the street of officers' houses that overlook the grounds. The howitzer is placed near the flagpole.
I'm a transplanted New Yorker who loves the Tucson climate. On New Year's Day I have a bit of fun calling my (snowbound) east coast friends to announce that I'm drinking coffee while sitting on my patio. (: