Would you buy a piece of this rock?

Just the other day the news arrived that the drummer of Led Zeppelin earned $ 9.6 million in 1979. Whew! That was a load off the old conscience. Scratch one species -- rock musicians -- from the endangered list.

But then we read a scare headline on the front page of the Wall Street Journal: "Is Rock Softening?" The subhead supplied an even more alarming answer: "Fans Are Deserting Concerts in Droves."

The statistics of a "horrendous" collapse -- second only to the auto industry -- followed. Business was off "a minimum of 20 percent." Why? The "baby boom" was over, the Wall Street rock analyst explained. And maybe, just maybe, the story went on, we are witnessing revolutionary "changing tastes of teen-agers" -- a phrase guaranteed to exhilarate, and terrify, any parent.

With our usual diplomacy, we submitted the Wall Street thesis to the nearest teen-ager. "Absolute nonsense!" she cried, or moderate words to that effect. Then, observing our deep concern, she offered to lend us her back file of Rolling Stone magazines to prove that rock is alive and well -- and not just in Argentina.

In no time at all, my amassed comforting evidence:

Bruce Springsteen has sold out his four concert dates in Madison Square Garden. The box office received twice as many mail order requests as any previous event in Garden history had generated.

Meanwhile, at Radio City Music Hall, the Grateful Dead sold 36,000 tickets in two hours. (The lines for the six performances had begun to form three days in advance.)

Across the Atlantic, Fleetwood Mac played to a week's worth of capacity audiences in London while the sales of the group's "Tusk" album went over four million copies.

Our in-depth research revealed that one out of 10 albums on the Rolling Stone Top Hundred Chart sold more than a million copies.

It was not only statistics that gave us "cautious optimism," to borrow an old Wall Street phrase. On his tenth album Captain Beefheart has recorded a tune called "Sheriff of Hong Kong," on which he plays Peking Opera gongs and sings in Mandarin Chinese. Is this the sign of a moribund art, we ask you?

Other indicators corroborated the impression that rock is still blue-chip. The T-shirt business has gotten so big that "bootleggers," peddling cheap Pakistani shirts, have moved in on the licensed T-shirt brokers, who pay royalties to the stars for use of their names and logos. The bootleggers, it is estimated, are doing a $50 million business.

Then there was the little incident in Wichita -- remember? Secret Service agents, scouting in advance of Rosalynn Carter, asked for complimentary tickets for themselves to a Jefferson Starship concert. Afterwards one of them requested, on White House stationery, an autographed photo, which he promised to hang up in his office, next to the portrait of the Carter family.

We have a law of culture that reads: Anything popular in Wichita, or with Secret Service agents, is popular forever. Our faith in the future of rock seemed doubly confirmed.

But we had hardly breathed the proverbial sigh of relief when we ran across an interview with Mick Jagger. "I'm afraid rock and roll has no future," the dean of rock and roll told his interviewer. "It's only recycled past."

And then our archives coughed up an even more ominous interview, with Billy Joel, who flatly warned us: "I am in no way set for the rest of my life . . . It's a recession, man. I'm like everybody else."

Is it time to print up the bumper stickers, Save the endangered rock musician?m Should we waste not a moment in setting up an impoverished Lead Guitarists Fund?

These are questions for the individual conscience. We have our own rock-recession test. Last month John Lennon sold a Holstein from his Syracuse farm for $265,000, leaving him with only 249 of the breed. At the time he turned down an offer of half a million for the cow's mother.

We're watching and waiting. If John has to pawn the mother, we're ready to put the rock musician on our endangered species list and take appropriate action. Our position is this: A nation that can bail out Chrysler is rich enough to bail out Billy Joel.