Federal and military personnel may have to take a smaller October pay raise than they anticipated if the White House, as expected, decides to shave the multibillion dollar increase as a gesture to the rest of the nation's employers and unions.

Although the amount of the October civil service-military raise usually is not announced until late summer, insiders believe the White House soon will go public with a plan to hold the raises below the 6 percent to 6.5 percent originally projected in the president's budget.

On Jan. 24, this column reported that "it is safe to speculate that the amount Carter will propose will be under the 6 percent he has budgeted for and could be as low as 5.4 percent." Now, officials say, even that 5.4 percent figure may be too high.

Officials say the economic picture, particularly in the light of the 100-day old coal strike, is even grimmer than in January when the president proposed that government, labor and industry hold 1978 wage and price increases "below" the averages of those increases for 1977 and 1976. If that kind of lid was put on October government pay raises, it would mean an amount of 5.9 percent or less - the average of the two previous years' increases.

Now, however, top administration inflation fighters are urging the president to keep the federal-military increase to 5 percent, and to let labor and industry know it now so they can exercise "voluntary" restraints.

In an internal White House memo last week, Barry Bosworth, head of the Council of Wage and Price Stability, suggested that a 5 percent lid be put on 1978 federal pay raises.

The importance of announcing an early lid on federal-military pay raises goes beyond the $500 million in direct pay savings to the government that would result if the raise were set at 5 rather than 6 percent. The federal-military payroll now runs more than $69.4 billion a year.

By demonstrating that government is willing to tighten its own belt, the nationale is, labor and industry would be put in a position in which it would be difficult to exceed the president's guidelines.

Locally, more than 300,000 white collar federal civilians and about 80,000 military personnel stationed nearby are due a raise in October. The increase is based on a government survey of private industry pay, and is designed to keep the salaries of government employes on a par with counterpart wages in the private sector.

A 6 percent raise for the typical white collar government worker here would amount to about $23 a week before taxes.

Nobody in government wants to go on the record to predict what the president will do about the federal-military pay raise. But off the record, the guessing is almost unanimous that the 6 percent raise already has been vetoed by "events," and that 5 percent for October is much closer to target.

Members of Congress who would champion a full-fledged federal-military pay raise in an off-year will not do it in 1978. That's because this is an election year and Congress is due to get the same pay increase as rank-and-file civil servants. In election years, the rule on Capitol Hill is that smaller raises are safer than big one, and no raise is the best reelection insurance.

Foreign Service Upgradings: The Senate Foreign Relations Committee approved yesterday promotions for 284 FS officers. This is the smallest promotion list State has sent to Capitol Hill in years. In response to many protests from FS officers, and some pressure from Congress, Secretary Cyrus Vance has promised to come across with additional promotions later this fall.

Postal Service Cuts: The House has approved legislation that would require the U.S. Postal Service to ask Congress before it makes any significant changes in service. Post Office-Civil Service Committee Chairman Robert N. C. Nix (D-Pa.) sponsored the bill, which is aimed at giving Congress the power to veto anything like the proposal to drop Saturday mail delivery.

Press Job: The Labor Department needs a Grade 12 or 13 public affairs specialist ($21,883 or $26,022 to start). Call 523-7435 for details.