Sayedul Alam is not much of a history buff, which is surprising, considering that his Middle Eastern grocery story, Kalustyan's, is located at 123 Lexington Avenue, one of the most historic buildings in the city. Blame the building's false, glass-and-aluminum façade, but it's easy to forget that Chester Arthur was sworn-in here as president of the United States -- the only president besides Washington to take the oath of office in New York City. Where else but New York could a building be a former presidential home AND the home of an outstanding mujadarra sandwich? Unfortunately, more people know about the lentils than the leader. "It really doesn't come up that often," said Alam, who is called upon only rarely to show the inaccessible, decades-old plaque that indicates that history once happened here. On the morning of Sept. 20, 1881, Arthur's home was surrounded by reporters after the news spread that President Garfield had finally died from being shot by a disgruntled office seeker three months earlier. Vice President Arthur (perhaps anticipating the "undisclosed locations" of Dick Cheney) had been holed up in New York to avoid the appearance that he was waiting in Washington for Garfield to die. But when Garfield died, Arthur was anything but pleased. The Times quoted Arthur's doorman saying that the veep was "sobbing like a child, with his face buried in his hands" (thank goodness for indiscreet doormen). That account placed Arthur almost exactly where the mujadarra is prepared today. A couple of hours later, Arthur took the oath of office as 21st president in the ground-floor parlor -- where you can get great deals on bulk nuts and spices. "Chet Arthur, president?" essayist Henry Adams said later in the day. "Good God!" OK, so maybe Chester Arthur was an accidental president, a political hack who became Garfield's running mate to balance the ticket -- but he was OUR hack, a great New Yorker who has been unfairly forgotten. "There should be a museum at 123 Lexington," said James Bradley, senior editor of the "Encyclopedia of New York City" and an Arthur champion. "He had significant achievements, from integrating city streetcars, to serving as the quartermaster general in the Civil War, to running the Port of New York." And as president, Arthur reformed the nation's civil service laws -- the very same laws, would you believe, that Al Gore ignored when he made those fundraising calls from the White House. "Chester Arthur was a great New Yorker," Bradley said. "He deserves his due." So until someone builds a museum, all we can do is head to 123 Lexington Avenue, grab a mujadarra sandwich and eat a toast to Chet Arthur, New Yorker. --30-- gersh.kuntzman@verizon.net