ONCE AGAIN the veterans of Vietnam are assembling to honor those who died there. There are many thousands of them in Washington today, no longer so young (their average age is now 38), some wearing old fatigue shirts or jackets that bear the names of military units and faraway battlefields, others in the civilian uniform of coat and tie. Many were here two years ago for the dedication of the Vietnam Memorial, whose black marble walls are inscribed with the names of 58,022 American war dead. Others have come who for one reason or another were absent from that first observance. Among them is the president, who is expected to speak at ceremonies tomorrow, Veterans' Day, dedicating a statue of three servicemen as part of the memorial. The memorial will then be turned over to the federal government, to become a national monument.

Like the war, the memorial has evoked strong emotions. The severity of its original design offended some, and the statue to be dedicated tomorrow was added to make it more widely acceptable. But in the two years since its dedication, the somber wall covered with names has evoked emotion of a different sort. The scene has been repeated countless times at this intensely personal memorial: a visitor searching through the names until one name is found, then weeping at the sight of it.

Someday the Vietnam Memorial may be viewed with the same detachment as a Civil War cenotaph in a courthouse square, with its list of Union dead. That happens when the tragedy of a person's dying young is diminished by the fact that those who knew and loved him are long dead too. But the veterans who are in our city are still very much alive. Much beer will be drunk this weekend and a good many war stories told, with the necessary embellishments. Along with a certain amount of solemnity, religious observance and military pomp, there is to be a concert featuring Frankie Valli and other musical people not likely to be mistaken for Julia Ward Howe.

This weekend's ceremonies are seen by many as another step in the process of postwar healing, of reconciliation between Vietnam veterans themselves, between these new veterans and those who served in earlier wars, and between those who fought in Vietnam and the civilian society that was so bitterly divided by the war. It would be hard for anyone to argue at this point that the memorial the nation takes custody of tomorrow hasn't done a great deal to help this healing along.