The Montgomery County Republicans' annual Lincoln Day dinner is usually a cordial, noncontroversial affair -- a time for renewing acquaintances, passing on political gossip, getting a look at young political prospects and listening to a speech by some prominent Republican or other.

The 1981 dinner promised to be no different -- until this week, when members of the local party's central committee learned that former president Richard Nixon had been invited to speak at the $20-a-head party on Feb. 12 at the Indian Spring Country Club.

The announcement, according to one central committee member, was greeted with "some incredulity and some extreme pleasure." There was no need for discussion -- the telegram containing the invitation had been sent to Nixon's New York offices last Friday, four days before most central committee members learned of it.

Nixon has not yet responded, according to central committee chairman Sheila Brandt, who authorized the invitation. Neither the former president nor his chief of staff, Nicholas Ruwe was available yesterday to comment on his plans.

"It's very possible that Nixon is emerging from the shadows of being a nonperson. The forbidden name can now be spoken," said Montgomery County State Sen. Howard Denis, referring to the Watergate scandal, which forced the former president to resign his office in 1974.

"Personally, I can never forget [what happened during] those years . . . I would never want to go through that period again," said Denis. "But for all his faults, Richard Nixon has a place in history and it's seldom you get a chance to hear from such an individual . . . I think it will probably sell a lot of tickets."

"The feeling [of some central committee members] was that the country did crucify this man and we thought it would be good to have him speak to us," said central committee member Carole Plante. In past years, 500 to 600 people have attended the annual dinners to hear such speakers as outgoing House Minority Leader John Rhodes or Vice President-elect George Bush.

"I'm just astonished that we would do this," said one central committee member who asked not to be named. "This was just announced. It wasn't possible to raise objections. It was a fait accompli."

If Nixon were to appear, it would not be the first formal public gathering he has attended since his resignation. In July 1978 he dedicated a recreation complex in Hyden, Ky. One month later, he hosted a fund-raising reception for the Orange County (Calif.) GOP at his San Clemente home.