It is almost time for RFK Stadium to rock.

It is almost time for John Riggins to roll.

It is almost time for the Redskins against the Cowboys, at 12:30 p.m. today at RFK Stadium for the championship of the National Football Conference.

The winner plays in Super Bowl XVII Jan. 30 in Pasadena, Calif., against either the Miami Dolphins or the New York Jets, who play Sunday.

The weather clearly could be a factor. The forecast called for intermittent light snow changing to rain with temperatures reaching into the mid 30s during the game. George Allen used to call that "Redskin Weather." Of course, George Allen said sunny and 80s was "Redskin Weather," too.

The oddsmakers are saying the Cowboys are favored to win by 2 1/2 points, a spread based more on history than local sentiment. The Cowboys have won the last six games between the teams going back to Nov. 18, 1979, including a 24-10 victory here on Dec. 5.

But the oddsmakers clearly have not been to RFK Stadium lately, where another capacity crowd of 55,000 no doubt will make the place shimmy and shake, and will make the Dallas Cowboys wish they'd brought along Texas-sized Walkmans to blot out the sound.

Said Tom Landry, coach of the Cowboys and star of that American Express commercial: "I never thought I'd be surrounded by so many Redskins."

"I think our fans are unique fans," Redskin Coach Joe Gibbs said yesterday in his final press conference of the week. "They're very different . . . I think the emotional lift our fans give us is a very important part of our team. I remember we had to struggle in some games early in the season. Without our fans, the outcome of those games would have been different.

"Right now, we need everything going for us. Everything has to go just right."

That is just what happened a little more than 10 years ago. Same teams, same site, and the Redskins prevailed in an NFC championship game that New Year's Eve in 1972 by a margin of 26-3. And now, on the eve of this game, the 'Skin Disease that afflicted the area is back upon us, the perfect plague in a harsh winter's week.

Yesterday, the signs were everywhere.

Downtown, there was an informal pep rally on the corner of Connecticut and L: lawyers in pin stripes, cabbies in flannel shirts, shoppers in down parkas and lots of banner-waving, "Beat Dallas" cheering and choruses of "Hail to the Redskins." Someone carried a stick with an effigy of Danny White, pierced by seven arrows.

There were a half-dozen vendors in the same area selling buttons, T-shirts, hats and pennants.

Darrell Johnson said he'd sold 99 buttons, many of them proclaiming, "Redskins #1 in '83" at $1.50 a button.

Renetta Turner said she sold out her stock of 300 Redskin pennants at $2 each.

And everywhere there were predictions.

"27-24 Redskins. If it's inclement weather, I'd say, 27-17," said Lloyd Thompson, who operates a beer and food concession on the stadium's mezzanine level.

"Sure, we win," said Gary Wilson, an unemployed accountant who says he wants his fellow fans in the stands to organize today.

"You know, wouldn't it be something if every time Dallas blitzed the fans yelled, 'Blitz, blitz.' Or every time they ran a sweep, we'd yell, 'Left, left,' or 'Right, right.' "

The Metropolitan Police say they are prepared for anything. There will be 200 officers at the stadium, to handle crowd control and traffic beforehand and to make sure celebrations don't get too out of hand afterward.

Assistant Chief Marty Tapscott recalled that during the Redskins-Cowboys game of 1972, almost everyone seemed to be in front of a television set watching the game. "During that four-hour period (today), crime probably will be very low," he said.

Metro ridership to the stadium should be very high. The subway will run its normal home-game service--extra trains on the Blue/Orange lines to move approximately 11,000 people who will ride the train to the game.

Buses also will run between the stadium and 11 parking lots in the city and suburbs.

The game will also be a bonanza for other businesses. Bars with large-screen televisions expect large turnouts. Liquor and beer sales should be up.

Abe Liss, head of Television Rental Corp., estimates he's rented 50 to 75 sets to people who just want them for the game. "I've been involved in this business for 35 years, since the days Sammy Baugh played for the Redskins," Liss said. "I have never seen the excitement and interest that I see for this game."

And why not? It's the Redskins against the Cowboys for the Super Bowl.

It is almost time