No, not Gracie Mansion.
No. 4 Gramercy Park West is being gutted, with some serious renovations going on. The residence, which is within the Gramercy Park historic district, was built in 1846 by Alexander Jackson Davis. New York City mayor James Harper (who started as a publisher; his company exists today at Harper Collins) bought the home in a year later and lived there until he died in a Good Friday carriage accident in 1869. In those days, a mayor or former mayor's home was signified by two lanterns on either side of the gated street entrance. It's unusual to see work being done on one of these sort of landmarks.
The workers outside said that three families live in the building now. Given the vigilance of Gramercy residents, I assume the improvements are on the up and up. The building is beautiful, adorned with some unusually intricate ironwork porches, so untouched by time that knotty twisted vines thread in and out of the iron.