Most observers believe the Los Angeles Raiders are the best team in the NFL. That's probably correct. They are the defending Super Bowl champion and they are off to a 4-1 start in the tough AFC West.

But they have failed to cover the point spread in their last three games, I'm delighted to report, having picked against them on all three occasions. It just might be that Al Davis' team is not going to get into the playoffs as easily as many fans think.

L.A. is tied with Seattle and Denver for the lead in its division. San Diego and Kansas City are one game off the pace at 3-2, which would tie Pittsburgh for first place in the AFC Central.

The Raiders must overcome the bad luck of having to play in the strongest grouping while being the prime target of every opponent. Every rival achieves an emotional high against them. Certainly that was the case in Denver Sunday when the Broncos won, 16-13.

What will help is L.A.'s moderate schedule outside its division: Minnesota, at Chicago, Indianapolis, at Miami, at Detroit and Pittsburgh.

Don't misinterpret. I'm not predicting the Raiders won't get to the playoffs. I'm simply suggesting that it will not be as easy as many think, not with jittery Jim Plunkett at quarterback.

Plunkett often performs nicely in the big games, but he can be a load for the Raider defense to carry against routine opponents. Only a team with the Raiders' outstanding overall talent could win, consistently, with a Plunkett at the controls.

This week's line finds the Raiders favored by 5 over Seattle, Washington 7 1/2 at Indianapolis, Tampa Bay 3 over Minnesota, Chicago 3 over New Orleans, Kansas City 5 over the New York Jets, Dallas 6 1/2 over St. Louis, Buffalo 1 over Philadelphia, Detroit 3 over Denver, Miami 5 at Pittsburgh, New England 2 1/2 at Cleveland, San Diego 3 at Green Bay, Cincinnati 7 1/2 over Houston, the Los Angeles Rams 3 over Atlanta, and (Monday night) San Francisco 3 1/2 over the New York Giants.

I'll take Seattle, San Francisco, Washington, Tampa Bay, Chicago, St. Louis and Atlanta for an imaginary $250 apiece.

Chuck Knox has rapidly developed the Seahawks into one of the league's best defensive units. The coach is a winner, wherever he goes, and he's going to take Seattle right back to the playoffs. Too bad he lost Curt Warner. The Seahawks defeated the Raiders twice during the regular season in '83 before losing, 30-14, in the AFC championship contest. They'll keep it close Sunday. Take the 5 points.

The 49ers are 5-0 atop the NFC West and 5-0 against the point spread. Every time they need help they make a trade with San Diego, Gary Johnson being the latest example. I have profound respect for the Giants' defense but the offense, once again, is struggling. Joe Montana should post enough points on the board to cover. Give the 3 1/2.

Washington has an excellent defense against the run, which is what the Colts do best. Curtis Dickey and Randy McMillan are underrated, operating behind a good offensive line. This is an excellent example of strength against strength. The Redskins, meanwhile, should move fairly well on offense, despite the absence of Charlie Brown. Give the 7 1/2.

The Bears looked good in losing to Dallas. We'll hope Jim McMahon is ready to throw the ball, something he couldn't do against the Cowboys. Walter Payton will go past Jim Brown in lifetime rushing while the Chicago defense keeps New Orleans under 20 points. Give the 3.

Tampa Bay tried desperately to lose a game it had won against Green Bay. The Buccaneers are life and death to cover against anyone, but they did manage to do so over the Packers, with the aid of overtime, and Minnesota's passing game seems to have lost something with the departure of Bud Grant. The Buccaneers play solid defense. Give the 3.

St. Louis moved the ball exceptionally well against Miami without Ottis Anderson. The Cardinals are going to score 24 or more points at Dallas. That might not be enough, considering the condition of the St. Louis cornerbacks, but the number is attractive. Take the 6 1/2.

Atlanta also has a good offense. The Falcons couldn't score a touchdown against San Francisco despite penetrating the 10-yard line on four occasions. The Rams' defense is sound, but the offense doesn't scare anyone. Take the 3.