Four years ago, a small, conservative think tank on Capitol Hill unveiled a 1,093-page blueprint designed to force the federal government to the right, and about 20 reporters came by for an explanation.

On Tuesday, a larger group showed up -- just to discuss one chapter of the organization's updated blueprint.

The organization is the Heritage Foundation. And its "Mandate for Leadership II," a compendium of more than 1,300 proposals for President Reagan's second term, has attracted attention because its 1980 "Mandate For Leadership I" became a bible of sorts for many in the Reagan White House.

Some members of the administration kept well-thumbed copies of the document, a wish list for the right wing, within easy reach during the early days of the administration.

"The second time Paul Revere said, 'the British are coming, the British are coming,' people would have paid attention," said Heritage Foundation vice president for research Burton Pines.

Mandate II was presented to the Cabinet last week, and Heritage Foundation officials said they began making the rounds to department heads to go through the document and show them how pull the government further right.

For four years the Heritage Foundation has had easy access to the administration, providing ideas as well as facts and figures.

Its less-government-is-best thinking is in line with Reagan and several of its board members, including conservative beer brewer Joseph Coors, long have been strong supporters of Reagan.

Heritage Foundation President Edwin J. Feulner Jr. is considered a key adviser to presidential counselor Edwin Meese III and his name has been mentioned recently for the "conservative" slot in the White House if Meese becomes attorney general.

In addition, three dozen or more Heritage Foundation employes found full- or part-time niches in the federal government, from the White House to the State Department to the Office of Management and Budget.

As one White House insider put it, "There are several think tanks that contributed, but Heritage had the most influence."

The Heritage Foundation has had far from a perfect batting average, however, with the Reagan administration.

According to a "report card" the foundation issued one year after Mandate I, about 60 percent of its proposals had been adopted or were in the process of being implemented.

Among the successes were many of the ideas on which Reagan had campaigned in 1980: cutbacks in many programs and taxes, increases in defense spending and reductions in federal work force.

The administration also loosened many federal regulations affecting industry and made regulatory agencies less adversarial. For instance, it stripped the Office of Surface Mining of much of its power and made the Occupational Safety and Health Administration more "cooperative," as the foundation had recommended.

And Reagan did push through block grants for education and other social programs and latched on to the Heritage Foundation idea of "enterprise zones" to revitalize decaying inner-city areas.

But, the administration did not pursue the idea of abolishing the Education and Energy departments after encountering congressional resistance. It did not try to deregulate trucking, in the face of opposition by the Teamsters union, which had endorsed Reagan. And it increased rather than ended federal support for highway maintenance.

Not only did the administration not try to eliminate the federal gasoline tax that finances road maintenance, construction and operation, but then-Transportation Secretary Drew Lewis helped push through an increase in the tax and an expansion of the federal highway program.

The report card showed that almost none of the changes proposed for the Justice and State departments had been accepted.

Feulner said he thinks that the administration will do better in following his foundation's lead in its second term.

Others on Capitol Hill and in the White House are more skeptical. They say the political climate -- the lack of a clear administration mandate and the potential for stalemate on Capitol Hill -- makes many of the things the Heritage Foundation seeks, such as new cuts in programs and major increases in defense spending, unlikely.

In addition, some of the proposals, such as making Social Security voluntary, were dismissed without even being discussed.

"I think their time has sort of passed, at least up here," said one Senate Republican. "Their ideas, or what I've heard of them, are too draconian to be achievable. The political momentum was there four years ago, but it's no longer there now."

In addition, the political situation at the White House may not be as supportive of their ideas as it was four years ago. If Meese departs for the Justice Department, the Republican "pragmatists" will dominate the upper echelons of the White House. They are less likely to pursue a conservative agenda that may lead to stalemate on the Hill.

One Republican insider said, "My guess is their report will be looked at and considered and probably not given as much weight as the last time around."