The answer is, yes bop a loo bop, a wop bam booom.

The cheerleader and the class clown and “the brain.”

They all showed up.

Identities from high school, the great American shaping machine. Identities left behind a lifetime ago, but never truly lost.

Members of the North Hollywood High School class of 1958 held a reunion recently. One woman stood outside the Sheraton Universal, gazing in horror at a group milling around the sign-in table, pinning on name badges.

“Oh my God, everybody looks so much younger,” she exclaimed.

She was turning around to go home when someone explained that this was another reunion--different school, class of 1978. She relaxed when she found about 340 of her own generation in a nearby ballroom.

But in this group, poised on the threshold of 50, she wasn’t the only one to hear mortality knocking and wonder about the odd lottery of time.

“This is such a strange age,” observed one woman. “Some of us are old already and some aren’t.

“I mean some of these people are wrinkled and gray and the women’s figures are gone and they’re in sensible shoes and they look the way I remember my grandparents. And there are just as many who look 10 or 15 years younger than that crowd and they’re still boogying and flirting. I mean, there are a lot of women here in miniskirts.”

And so there were, most of them looking quite good enough to slug it out, gam to gam, with the Brigade of Second Wives. Including her, as she pranced off to dance to “Tequila.”

It was a cliche of 1958, from parents and grandparents fixated on the gentler music of Broadway and Tin Pan Alley, to ask teen-agers: “What are you going to do at reunions 30 years from now? Dance to ‘Tutti Frutti’ when you’re 45 years old?”

If anyone’s still interested, the answer is yes bop a loo bop, a wop bam booom.

The class of ’58 bounced their no-longer- adolescent bodies and snapped their graying heads to “Shake, Rattle ‘n’ Roll,” and “Kansas City” and “The Wanderer” and Elvis doing “Blue Suede Shoes.”

To credit those vanished elders, however, a large matron bobbing and weaving and singing “I’m like a one-eyed cat peeping in a seafood store” is a sight previous generations should not have been expected to imagine.

In 1958, when they set out into the world, rock ‘n’ roll was still a novelty, expected to disappear as soon as the teen-agers danced all the hormones out of their systems. The Russians had launched Sputnik the previous October, setting off a national panic about the competitive level of American education that faded away after a few federal loan programs.

The class of ’58 were the “silent generation” in college for awhile, and then they divided as the Old America died with John Kennedy. Some joined the upheavals of the 1960s, replacing Ozzie and Harriet with Jimi Hendrix and Gloria Steinem and eventually becoming senior yuppies.

Others who started out down the same river headed for the bank when the rapids got crazy and walked along the shore in their parents’ footprints, marveling at what their friends were up to.

Three of the class were killed in Vietnam.

Sammy Peltzer married an Israeli girl and went home with her. He’s a lawyer for an Israeli aircraft manufacturer and a reserve army officer, serving as liaison to the Multi-National Peacekeeping Force in the Sinai. Allen Hain became the chief deputy counsel of Marin County.

Laela Handy--a tall, slim brunette her friends called “the brain” because she was so studious--is assistant dean of education at Cal State Fullerton. She’s working on her Ph.D. and has been moonlighting for 13 years as a security guard at Disneyland, “just because I really do believe that it’s the most magical place on Earth.”

Like a number of women at the reunion, she has an adult child but is single again. She wore the same strapless white lace formal she wore to the senior prom. “I just ran across it three weeks ago in the attic at my mother’s house. It still fits.”

Thomas McNett wore a tuxedo with corduroy shorts and sandals. Why? “Well, life gets a little too serious for me sometimes,” he said. He’s an emergency room doctor in Modesto. “And I don’t get to wear suits in my business. I’m in blood and guts.”

Sharleen Cohen of Encino was Sharleen White back then, when she wrote the class motto: “Today’s endeavor, tomorrow’s success.”

She kept writing and as “S. Cooper Cohen” has published five novels. The latest is “Love, Sex and Money,” about three women living through the social changes from the early 1960s to the late 1980s.

A former cheerleader, she started writing to prove that “social butterflies can excel, too,” she said.

John Mateja, a tall man with a sun-streaked blonde beard, bummed around the world for years, taking odd jobs, until he met a girl in Australia. They live in Auckland, New Zealand now, where he is--this will break up his old friends, he predicted--a high school teacher.

“I was the class clown. Now when the kids in my class come at me, I figure it’s karma.”

While many of his classmates are grandparents several times over, his own children are 5 and 9.

“There were kind of two philosophies when we graduated,” he said. “One group got married right away and settled down. A few of us wanted to see the world first. But now we’re the ones who are settled down and those other guys, their kids are all grown up and they’re free to do the kind of things I did in my 20s.”