There's no rush to climb on the Reagan bandwagon in Richmond: Last year, when Democrat Charles S. Robb kicked off his campaign for governor, the high school band from his alma mater, Mount Vernon High School, made the trip to Richmond to provide music for the rally. But school officials in Richmond and Henrico County have politely declined an invitation to provide a high school band to play at a rally in the Virginia Capitol Wednesday.

The event, to raise funds for Rep. Paul S. Trible, the Republican candidate for the U.S. Senate, will feature an appearance by President Reagan. "Even though we would be honored to play for the president of the United States," said Henrico School Superintendent William C. Bosher Jr., "we could not use the school system . . . in a partisan activity." Same tune in Richmond, where Dr. Nathaniel Lee, director of school-community relations, declined "because we cannot involve public school students in partisan politics." Republicans won't have to sing the National Anthem a capella, however, as officials in rock-rib Republican Chesterfield County told Rep. Thomas J. Bliley Jr. they'd be honored to provide a band.

Some people think Marvin could be elected again, but that's what they also say about Nixon: The high point of a Democratic unity rally at Blob's Park (no, it's not Bob's) in Anne Arundel County the other night was the introduction of Marvin Mandel, the former governor convicted of political corruption. Mandel's popularity was evidenced by the applause he got throughout the large hall, even it appeared, from Gov. Harry Hughes, who ran in 1978 against Mandel-style corruption.

Mandel went to the event at the invitation of its organizer, basketball star and political fund-raiser Tom McMillen.

Because the event was a fund-raiser, featuring two presidential hopefuls, Sens. John Glenn and Gary Hart, the big winners were the normally fractious Anne Arundel Democrats, and especially county executive nominee James Lighthizer.

Every time someone suggests this guy could do the job, he runs for it: Maryland state Sen. Harry J. McGuirk, who appeared to be a politician without a post after he lost the Democratic primary for governor, may have found a position after all: he has tossed out his name as a replacement for Baltimore City Council President Walter Orlinsky, who pleaded guilty this week to an extortion charge and will be stepping down.

The Baltimore Sun, which pooh-poohed his quest for the governorship, suggested this week that McGuirk would be "well-suited" to the task of interim council president until city elections are held next year. Then, the Sun declared, he could become one of the city's lobbyists in Annapolis.

McGuirk took the suggestion to heart and scheduled meetings yesterday with several council members, including Clarence Du Burns, the council vice president. Du Burns has been considered most likely to succeed Orlinsky--and would be the first black to take that post--but because of old animosities between Du Burns' east side political group and several black organizations on Baltimore's west side, his effort may be stalemated. This is where McGuirk enters--as an interim solution while all sides try to work out their problems.

All of the speculation has been keeping McGuirk's post-primary spirits up. Thursday night, when Marvin Mandel saw McGuirk at the Democratic rally in Anne Arundel and asked him how he was doing, McGuirk, smiling and relaxed, replied, "I'm looking for a job." To which Mandel responded, "The way I understand it, you've got a few all lined up."