New York Times columnist Anthony Lewis and ABC television newsman Steve Bell will unveil a memorial plaque at the National Press Club Monday dedicated to 265 journalists killed in the line of duty. Associated Press Bureau Chief Charles Lewis will talk about AP's efforts to secure the release of their Beirut bureau chief, Terry Anderson, who has been held hostage in Lebanon since March . . .

Ken Kragen, president of USA for Africa, was to receive a United Nations Peace Medal last night for his efforts in arousing public awareness of the African hunger crisis. The presentation was scheduled to take place at the World Bank . . .

Oscar-winning director and screenwriter Billy Wilder has been named the 14th recipient of the American Film Institute's life achievement award. In announcing the decision, AFI cochairman George Stevens cited Wilder as "a writer-director who has created a sparkling body of work that meets that AFI criteria of standing the test of time." Wilder, 79, won his Oscars for "The Lost Weekend," "Sunset Boulevard" and "The Apartment" . . .

Motion Picture Association of America President Jack Valenti told the Senate Permanent Subcommittee on Investigations that creating a new movie rating category to warn parents about the visual depiction of drug use in films would be confusing. "We have five categories now -- how many more can we handle?" he asked. He said yesterday that within the next two weeks the industry's voluntary rating board is expected to recommend that any film depicting drug use carry a PG-13 at the minimum . . .

There has been considerable speculation about when the brat couple, John McEnroe and actress Tatum O'Neal, will make their arrangement legal. Will they marry? The Paris-based sports newspaper L'Equipe, quoting a newspaper from southwestern France, said the world's No. 2 ranked tennis player has invited a French chef to prepare a dinner for 30 people Nov. 16 in Los Angeles. President Reagan was said to be among the invited guests, but with the U.S.-Soviet summit coming up two days later, his attendance would seem to be unlikely at best. The newspaper Sud-Ouest speculated it may be a wedding dinner for McEnroe and O'Neal. But then, they might be formally announcing their engagement, or for that matter, inviting a few friends over for a French dinner . . .