Federal and postal workers may find themselves under Social Security within the next couple of years no matter what happens in this week's congressional elections.

In mid-November a blue-ribbon, 15-member panel that has been studying federal pension systems will make its report and recommendations to the president and Congress. Insiders say it is almost certain to recommend putting government employes, who now have their own independent retirement system, under Social Security.

The question is whether the commission will propose Social Security coverage only for federal-postal employes hired in the future, or whether it will recommend putting everybody now in government under the system.

Federal and postal unions are prepared to fight mandatory Social Security coverage, whatever its form.

Most of the unions are urging members to vote for Democratic congressional candidates who they feel will deal more kindly with government workers over the next two years. But they expect a big push from Congress to bring government workers -- the only major group of employes in the nation outside the system -- under Social Security, no matter what the political lineup.

This current Congress has already taken two major steps toward bringing government employes under Social Security.

Beginning in January, government workers will start paying the Medicare tax portion of Social Security. That will amount to 1.3 percent of salary (on amounts up to approximately $35,000). The Medicare tax bite will cost government workers anywhere from $100 to about $450 a year, depending on their salaries.

Congress has also revised the payment date for federal-military retiree cost of living adjustments (COLAs) to coincide with those for persons under Social Security. Government retirees will get 1983 COLA raises in May. In 1984 they will get the COLA in June and in 1984 they will get the COLA adjustments in July, the same as persons under Social Security.

Legislation changing the effective date of federal-military COLAs (which previously came in March) is supposed to be a temporary economy move

The COLAs are supposed to return to their March effective date in 1985. But insiders say the effect of moving federal-military inflation adjustments to the same effective date as Social Security increases is more than coincidence, and just one legislative step closer to mandatory coverage for government employes.