In line with its fiscal 1983 appropriations bill, the Federal Communications Commission is dropping two of its seven seats next month. The move will cut nearly $400,000 from the agency's annual budget.

Joseph R. Fogarty, a Democrat who has served on the commission since 1976, is leaving at the end of a regular seven-year term, which expires June 30. Stephen A. Sharp, a Republican who began serving a special term in October, 1982, is leaving at the same time.

Commissioner Anne P. Jones, a Republican who began her term in 1979, is retiring next week to keep a long-deferred promise to herself to return to the private sector. Her stint on the board was not scheduled to end until June 30, 1985.

Jones' seat most likely will be taken by a fellow Republican, which raises an interesting question.

Speculation at the commission had been that Jones' early departure would ensure a seat for Sharp on the restructured, five-member panel.

Sharp, a former FCC general counsel, had been a loyal trooper in the Reagan administration's campaign to deregulate the communications business. Jones, who was appointed by President Carter, was moving out to avoid a showdown with Sharp, the speculation went.

But Sharp contends that he has no designs on Jones' seat. And Sharp has no desire to go through another round of Senate confirmation hearings to gain reappointment, according to some FCC sources.

No more than three of the five members on the reorganized panel can come from the same political party. The commission temporarily will have four members, two Democrats and two Republicans, after Fogarty, Sharp and Jones leave.

The remaining Republicans include FCC Chairman Mark S. Fowler, whose term ends June 30, 1986, and Mimi Weyforth Dawson, whose term expires in 1988. The remaining Democrats include James H. Quello, who was nominated by President Nixon in 1974 and reappointed by President Reagan to a term that ends next year, and Henry M. Riviera, also a Reagan appointee, whose term expires in 1987.

The FCC operates on a $80 million annual budget. Cutting two of the agency's seats and their accompanying staffs would save nearly $390,000 annually, FCC officials said yesterday. Still, the agency expects a budget in the neighborhood of $90 million for fiscal 1984, officials said.

One of the departing FCC staffs will move, almost as a unit, into the private sector.

Fogarty is taking his two legal assistants, attorneys James E. Graf II and H. Russell Frisby, to the law firm of Weil, Gotshal & Manges, where Fogarty will specialize in communications law.