The posse is in town now. So finally, the Washington Redskins will play the Dallas Cowboys tonight at 9 o'clock in a season opener bursting with so much hype, it would blow a dome off RFK Stadium if it had one.

"You can see it as King Kong versus Godzilla," said Redskins wide receiver Charlie Brown, "or maybe like the Ali-Frazier showdown."

A local limousine service offered to bring each of the Hogs to this game in his own regal way. "We couldn't do it before this game. It's too important," said guard Mark May. "But maybe after . . . "

Redskins tight end Rick Walker, creator of the Fun Bunch that celebrates Washington touchdowns, promises new tricks.

"You'll see the new Fun Bunch in action," Walker said confidently, "at about 9:20-something Monday night."

The oddsmakers insist it's "Dallas by 2 1/2." Dallas Coach Tom Landry, whose team lost its first opener in 17 years last season (Pittsburgh won, 36-28), views this game with his standard keen sense of strategy. He's not 202-115-6 for nothing, you know.

"This game is one of field position," Landry said. "The thing that won the Super Bowl for Washington last year was good defense, their kicking game and the fact they didn't commit turnovers." These, he said, are the things his Cowboys must reverse.

Underneath all the Redskins' surface talk--"It's just one of 16," Coach Joe Gibbs says, Memorex-like--some Redskins will admit that this opener carries extra meaning. They want to prove, before the 123rd consecutive sellout at RFK and a national television audience (WJLA-TV-7, locally), that they will not be affected by the NFL's modern-day force of gravity:

It goes thusly: What goes up to Super Bowl victory one year, comes crashing down to earth the next year. As the game approaches, it seems to take on greater meaning for these Redskins. Even quarterback Joe Theismann, who told a reporter Friday that this was just another game, said on network television yesterday that all the hype had made this game of the same magnitude as last year's 31-17 victory over the Cowboys in the NFC title game, maybe more important because "we're the champs."

On the surface, you see defensive end Dexter Manley talking tough. He paraded around the Redskin Park locker room Friday, telling the world at large, "The Cowboys are punks."

Then, you see Tony (Mac the Sack) McGee, 13-year defensive end, speaking the voice of experience, saying, "No one can live off last year's groceries . . . Dallas is a good team."

The statistics of games past show that the key to the Redskins' offensive production rests not merely in establishing a running game, but rather in drilling a running game into the opposition. The Redskins have won 10 straight games in which they have run the ball at least 40 times. They have lost seven straight, however, in which they have run the ball 30 times or less.

The fact that the Redskins ran the ball just 17 times in the 24-10 regular-season loss to Dallas last year and that they ran it 40 times (John Riggins ran 36 for 140 yards) in the 31-17 NFC title-game victory and the fact that they didn't lose a fumble over the last five-plus games (378 offensive plays) of last season, likely dictates Riggins left, Riggins right, Riggins up the gut tonight.

Theismann says he gets riled for the Cowboys: "When I get ready to play the Cowboys, I get ready to get physically abused," Theismann said. And he wasn't referring to the fact he was sacked seven times in the loss to Dallas last year.

"If I get the ball, I won't run out of bounds against Dallas. If we need a yard for a first down, I'll just drop my little shoulder pads or I'll hook slide," Theismann said, "like Ty Cobb."

Dallas is traditionally tough against the run. Last year, though, the Cowboys yielded 112 rushing yards per game, ranking seventh in the 14-team conference. And in its 3-1 preseason, Dallas yielded a ghastly 175 rushing yards per game.

But, oh how those Cowboys can run on offense. Often enough, it is Tony Dorsett doing the running. Two years ago, in Gibbs' rookie Redskins season, Dorsett burned Washington for 132 yards the first game, 115 yards the second game. Naturally, Dallas won both those games.

Last year, though, the Redskins limited Dorsett to 57 yards in both games. The Washington anti-Dorsett strategy for tonight is simple enough.

"The key to stopping Dorsett is just to physically beat the hell out of him," Redskins linebacker Mel Kaufman said. "You have to make him run inside. You have to hit him hard, again and again. Hit him hard enough and he'll cough it up."

Such meanness fades to trepidation when the subject is the Redskins' secondary. This is the place many feel Dallas quarterback Danny White will test over and over. Rookie left cornerback Darrell Green replaces holdout Jeris White and seven-year veteran Curtis Jordan replaces Tony Peters (who awaits sentencing on drug charges) at strong safety.

"Darrell is getting better," said Richie Petitbon, coach of the Redskins' defense. Petitbon says he will try to calm Green before the game. "I haven't talked to him yet, but I will," he said.