If the current economic recovery is sustained, as seems likely, better brace yourselves for an instant rewrite of history. Joyous, as they should be, that the economy is over the recession, Reaganauts will be claiming that Reaganomics has been vindicated.

It hasn't: the economy, which is showing signs of life because the Federal Reserve Board finally eased up on interest rates, has a long way to go before it gets back to where it was three years ago. Billions in national output and millions of worker-years of employment have been lost forever.

Reagan has not, by any objective standard, delivered on his promise to produce a painless recovery from the high inflation rates he inherited from President Carter, while simultaneously pledging to lower tax rates, regenerate private initiative, boost defense spending, reduce civilian outlays, balance the budget and reduce unemployment. Clearly, Reaganomics promised too much.

Nonetheless, any sitting president would claim credit for whatever improvement has come along--emphasizing lower inflation and lower interest rates and de-emphasizing the unemployment totals and idle factory capacity. No one should expect Reagan to do anything else.

Another way of looking at things is suggested by University of Minnesota economist Walter Heller, who was chairman of the Council of Economic Advisers under John F. Kennedy. Heller is even more bullish on short- term economic prospects than Reagan's chairman, Martin Feldstein.

But Heller makes this judgment because, in his view, Reagan has been abandoning Reaganomics. Heller cites the big tax increase ($98 billion) of last year, the president's willingness to compromise on a jobs bill, and approval of the Fed's move away from a rigid monetarist policy to one that focuses more on getting interest rates down.

Said the Fed Chairman in a Feb. 16 policy statement required by the Humphrey-Hawkins Act: "I neither bewail nor applaud the circumstances that have put a greater premium on judgment and less 'automaticity' in our operations; it is simply a fact of life."

These moves away from supply-side and monetarist ideology have the Reagan right wing up in arms. "(Reagan's) vision has been dimmed, his message clearly suffering from the mushy capitulationist advice that has become the hallmark of his chief of staff, Jim Baker," said the conservative publication, Human Events, after the State of the Union message.

In my view, both Heller and the right wingers overstate the extent to which Reagan has trimmed his basic beliefs and programs. The reality is that Baker and other White House aides came to understand it was essential to make the president look more compassionate about the unemployed, and to defuse the notion that his tax program mainly benefited the rich (which is true), or that budget cuts have mostly hurt the poor (also true).

But everything that has been said since the State of the Union shows the president is, with some modest exceptions, sticking to his key priorities:

A rapid buildup of the defense establishment (if anything, the costs will be even higher than first estimated).

A commitment to the three-year personal tax cut, which is scheduled to deliver a 10 percent reduction in rates on July 1, 1983.

The highly controversial tax-indexation scheme, scheduled to begin in 1985, designed to prevent "bracket creep."

The $98 billion tax increase last year, cited by Heller, was just one-seventh of the "Reaganomics" tax reduction in 1981, and did very little to affect the dramatic redistribution of wealth to the high-income families accomplished under the original legislation.

So the way I see it, Reagan has made the minimum adjustment in ideology that any president makes as he confronts the realities of his Oval Office. And his right-wing associates have much less to worry about than do the Democrats or anyone else worried about the huge deficits in the "out years."

And in terms of the economy--in the short run at least--Reagan has the upper hand. Recently, Democratic Sens. Gary Hart of Colorado and Tom Eagleton of Missouri heard Heller deliver a very upbeat economic forecast. When Hart--an eager beaver after the 1984 Democratic presidential nomination--asked Heller for the political meaning of his economic forecast, Eagleton jumped in with the answer.

"What it means, Gary," he said, "is that you'll still be in the Senate."