With a final skirmish over pay for so-called double dippers. President Carter's landmark legislation to revise the civil service system officially cleared a House-Senate conference yesterday.

The Senate could take up the bill for final action Friday or Saturday, with House action possible early next week, congressional sources said ReP. Morris K. Udall (D-Ariz.), conference chairman, said the final conference report would be signed and filed by 6 p.m. today.

The major conflicts between the House and Senate versions had been worked out last week.

In yesterday's final wrapup session, however, Sen. Ted Stevens (R-Alaska) threatened to torpedo the whole bill unless the conferees agreed to weaken a provision designed to limit the annual federal pay of high-level military retirees employed by the government, referred to by several conferees as "double dippers."

The original measure, sponsored in the House version by Rep. Patricia Schroeder (D-Colo.), would limit to $47,500 (for executive branch employes) or $57,500 (for members of Congress) the amount that high-ranking retired military personnel could earn from their combined military pension and federal salary. Because no such limit now exists, some retirees collect as much as $80,000 in federal checks annually.

The Schroeder provision did not apply, however, to regular military retirees already employed by the government.

The change won by Stevens yesterday adds to that category some 1,500 military reservists who also will be protected against any loss of pay - those who hold certificates of eligibility for retirement pay at age 60 and who already work for the government, but have not yet reached age 60.