Veterans of the Vietnam War came from up and down the East Coast in search of old friends and celebration. But most of all, they came to the Capital Centre yesterday for the music that is forever associated with the event that shaped their lives in so many ways.

In attendance at the benefit concert for Vietnam veterans were oldsters and youngsters alike. Some had been in diapers when the war in Vietnam was fought, and some once voiced their opposition to the war but have since found that their objection did not mean they opposed the warriors themselves.

But, appropriately, a significant percentage of the audience was composed of veterans and their families.

"I came here to hear the music, to hear what people are saying and because I felt, 'Hey, it's been a long time,' " said veteran Donn Shepherd, 37, a magazine production manager from Bergen, N.J.

"You know Otis Redding's 'Sitting on the Dock of the Bay?' " asked his friend, 37-year-old Bill Warner of Keene, N.H., who served in Vietnam in 1968-69. "We used to say, 'Sitting on the DMZ.' " The demilitarized zone, at the 17th parallel, was the buffer area between North and South Vietnam.

Asked what he does now, Warner replied: "I meditate."

The concert location's last-minute switch from RFK Stadium to the Capital Centre meant some fast footwork for a number of concert-goers.

Bobbette Smith and Jettaka Bell, medical service Army corps officers from Richmond, did not discover that the concert had been moved until they were about to get off the RFK Stadium subway stop.

After being informed of the switch by a Metro official, they made their way to the Capital Centre, where they got new tickets. "It's been a lousy day so far," Smith said early in the evening.

Apart from the fact that their fathers had served in Vietnam, the two who work at the Army's 85th Evacuation Hospital in Richmond attended because "it sounded like a special concert, especially with the artists who are here," said 30-year-old Smith. "We thought we might see the Woodstock of the '80s."

Jerry Iulo, 39, found camaraderie in the event. "It's got a lot of old songs, and everybody's like a long, lost brother. They all know what you've been through," said the Milford, Conn., resident, who was wearing a medal-bedecked, full-dress Army uniform and who had gone to Vietnam in 1965, "when I was 17." He was a prisoner of war for 18 months.

With him was his son, Gerard, 13, who has learned all he knows about Vietnam from his father, Iulo said.

"It's my era," said former Marine Henry Lacaillade of Raritan, N.J., who made the trip with some Vietnam buddies. Like most veterans at the event, they paid $15 each for their tickets, though the event's sponsors originally said veterans could attend free.

"If it's going to go to a cause like disabled vets, I can see it," said 38-year-old Billy Ray Smith of Fort Washington.

"I came to see my friends and visit my fellow vets," said the painter, who served in Vietnam with the 173rd Airborne Rangers in 1968-69.

Among those who bought tickets at the door was Chris Marens, 36, of Daytona Beach, Fla. He and his 8-year-old son, Brian, left home yesterday to attend the concert and visit the Vietnam Veterans Memorial, said Marens, who was at Pleiku in 1969 with the 4th Infantry Division.

"It's the first thing I've done connected with Vietnam since I left the Army," Marens said.

So why now? "It's an obsession," he said. "I guess . . . maybe there's a chance I can dump some stuff."