Yes, it’s true, the town of Southampton, New York, with its 55,000 year-round residents -- and its deserved reputation as a summer playground for the rich and famous -- now has its very own counterterrorism squad. Its members were first sighted in April, when cops wearing bulletproof vests and carrying fully loaded AR-15s showed up at the Bridgehampton Half Marathon, where they spent most of their time milling around the finish line.