Aha. Good eyeball Duke. I don't see installing AAA guns right in Harlem Might depend on what the definition of AAA is though. Didn't NIKE come online about that time? If so, they would probably put it on one of the islands around NYC but maybe in a park?
Yes, there were definitely SAM sites protecting NYC, but according Wiki, no US SAM was operational before 1953. That's at least five months before this claim. Besides, the claim specifically says "anti-aircraft guns." I think the radar directed, 75mm "Skysweeper" would have operational by 1952. Probably still WW2 120 mm AAA around in 1952, and lots of smaller stuff. Doubt there were many smaller caliber AAA in NYC , that's primarily intended for lower altiude threats. I don't think Soviet jets strafing Manhattan was high on their worry list.
Regardless of the specific type guns involved, you'd think what amounted to large artillery pieces going off in a populated area would have caught peoples' attention. Reminds me of a "researcher" who wrote a book about what he claimed was open combat between the US and aliens during the 1952 UFO wave along the east coast. In the book he claims aliens attacked and heavily damaged a number of US airbases, including MacDill AFB in Tampa. Anybody who's been to MacDill knows it's also surrounded by populated areas and sits on Tampa Bay. You'd think somebody would have noticed a pack of flying saucers attacking an airbase.