Those White House reporters came to their special briefing yesterday to meet an official on "economic monetary policy." He wasn't dressed like the usual expert. He was wearing a baseball cap and work clothes. He looked out at the assembled reporters and said, "You all look awful familiar. Were some of you on the Greyhound with me and Edna?" It was, of course, actor Jim Varney, one of the most familiar faces and voices in television commercials.

"I figured maybe Vern was here. We were just going to go check out that Smith Brothers Museum. And besides that, he's got my lunch money," he said. Varney's visit was set up by presidential spokesman Larry Speakes as a joke on reporters, who were relieved it wasn't a briefing on monetary policy. After his "briefing," Varney said he had to "go communicate with Mr. Reagan here -- part of being a good neighbor, you know? I gotta help him with his storm windows." And then, like any good Washington official, he promised, "We'll do lunch." Hart to Hart

Democrats for the '80s, Pamela Harriman's political action group, is holding its annual black-tie fundraiser tonight at the Ritz-Carlton. Since the money raised will benefit the Democrats' Senate Majority '86 drive, some 40 senators are expected, including John Stennis, Robert Byrd, Edward Kennedy, John Glenn, Paul Sarbanes, Gary Hart and Christopher Dodd.

Virginia Gov. Gerald Baliles and Kentucky Gov. Martha Layne Collins are expected. There'll be enough speeches to satisfy any politician's heart, including some by Harriman, Sen. George Mitchell, Sharon Percy Rockefeller and Collins. The event of the evening will be handled by Sen. Wendell Ford, who will auction off a box for six at the Kentucky Derby. And then there will be a brief Kitty Carlisle Hart concert. Harriman said she decided to fix the program to include Hart's full name after a dinner guest called her and, seeing that "Mrs. Hart" was singing, observed, "I didn't know Lee Hart could sing." From the President's Pen

New York art buyers are getting a unique opportunity tonight. Not only will they be able to bid on paintings by the late actor Henry Fonda, but they also will have the opportunity to buy the works of another famous man not generally known as an artist. President Reagan has donated seven signed doodles for the auction to benefit Very Special Arts.

While this is the first public appearance of Fonda's art, it is also a rare viewing of the work from the White House. The presidental doodles are of a horse and six faces. The auction, cochaired by Shirlee Fonda, widow of the actor, and Jean Kennedy Smith, founder of Very Special Arts, will be at New York City's Ritz-Carlton. Other artists' work on sale includes that of Ansel Adams, Peter Max and other celebrities such as Peter Falk, Marcel Marceau, Suzanne Pleshette, Elke Sommer and Loretta Swit. End Notes

The Securities and Exchange Commission is expected to announce tomorrow that its secretary, John Wheeler, will be leaving at the end of next month. Wheeler, who is chairman of the Vietnam Memorial Commission, has received a grant so he can work full time on the Project on the Vietnam Generation, housed at the Smithsonian Institution. Wheeler, who wrote "The Wounded Generation" with Al Horne and "Touched With Fire: The Future of the Vietnam Generation," said the project is to sponsor scholarship and research on the generation of the Vietnam war years . . .

Royal Watch: Those horse-loving royals seem willing to go the extra mile. Capt. Mark Phillips, husband of Princess Anne, is scheduled to be at the Patrick East Business Center in Frederick, Md., today to participate in a ribbon-cutting ceremony at the establishment of the first American outlet of Rice Trailers Ltd., a box trailer manufacturer based in Leicestershire, England. Avid horseman that he is, Phillips uses Rice trailers. He reportedly came to the United States specifically for the opening . . .