Requiem for a heavyweight.

Lou Grant rolls down his sleeves for the last time tonight. He will never roll them up again. Whatever minor complaints one might have about the "Lou Grant" show or about the off-screen political misadventures of its star, Ed Asner, this is a program that will be missed. CBS has nothing remotely as serious or substantial on its new fall schedule.

Unfortunately for one and all, there are no choruses of "It's a Long Way to Tipperary" in the city room of the Los Angeles Tribune to commemorate the falling of the ax (as there were when Lou, Mary, and the rest of the gang wrapped up "The Mary Tyler Moore Show" five years ago); when the cast and crew of "Lou Grant" filmed this show -- a new one, not a rerun, and the last episode CBS will air in prime time -- they didn't know it was the last one. They had every, or nearly every, reason to believe they would be back this fall for a sixth season.

Instead, one month after the episode was filmed, "Lou Grant" was canceled. CBS has never convincingly denied that the cancellation was based partly on Asner's politics -- his sponsorship of a medical relief committee for war victims in El Salvador and his activist rampage as president of the Screen Actors Guild.

Even though it wasn't designed as a farewell, however, the episode, at a farewell, however, the episode, at 10 on Channel 9, has an elegiac air. When Lou rolls his sleeves down near the final fade-out, we know it's for the last time, even if he didn't. Actually, the Grant character remains in the background of this episode, called "Charlie" in honor of Trib managing editor Charlie Hume, played by Mason Adams.

A tight, deft script (by Michele Gallery) and level-best, conscientious performances (directed by producer Seth Freeman) -- both typical of the series' overall excellence -- combine to demonstrate how even bighearted good eggs like Charlie Hume can be backed into corners that require them to play the heel. Charlie faces one crisis after another and tries to balance the feelings of those involved against the practical realities of his job.

Billie Newman (Linda Kelsey, one of the series' most dependable soldiers) demands to be transferred to Sacramento to be near her husband. Assistant city editor Art Donovan (Jack Bannon) fears his new girlfriend is pregnant and afraid to tell him. A young reporter has been found guilty of accepting a generous loan from a man about whom she wrote a laudatory puff piece. And Charlie's 25-year-old son, he mopes, has flipped out on Krishna.

When the Trib's publisher, Mrs. Pynchon (Nancy Marchand), twice meddles in personnel decisions he has made, Hume stomps up t her office for a brief tantrum. "So let me do my damn job!" he shouts. "All right!" she shouts back. Charlie Hume is trying to do the decent thing. "Lou Grant" tried to do the decent thing, for five pretty commendable years, and it often succeeded.

The way the characters behave seems, as usual, the way characters in this kind of situation would behave, and it's just as well the series is not going out on one of its social-issue notes, because there doesn't have to be any ideological tap dancing to get in the way of the drama. "Lou Grant" had ups and downs like everything else, but often it would turn a corner to find and illuminate some subtlety about people and the way they interact that would make one sit back and say to oneself, "Bull's-eye!"

The "Lou Grant" set has now been torn down at MTM Enterprises ih Studio City, Calif; it was turned into the set for "Remington Steele," an upcoming NBC detective series. Lance Guest, who makes a guest-star appearance on tonight's show, was to become a regular this season; thus he makes his debut and his swan song at the same time. As for Asner, he appears to have landed oh his feet, to say the least: according to Hollywood trade papers, he is going to work and keep his liberal credentials intact as well, first by starring in a fictionalized movie version of the Rosenberg spy case, then by playing the tortured Argentine newsman Jacobo Timerman in a TV movie.

Tonight's finale ends with a slow camera pull-back from the old Trib newsroom. We're going to miss that place. We're going to miss it plenty.