The way Lyn Nofziger remembered it, the last time the Republican National Committee held its winter meeting during a presidential election year, members and guests forgot to check their political long knives at the door.

"Believe me, it was nobody in '76," the former Reagan aide was saying as he looked over the camp-and-cocktail crowd gathered Friday evening at the open-house reception for visiting RNC members in the new wing of the Dwight D. Eisenhower Republican Center on Capitol Hill, "There's less tension here this year. We've got so many running, the antagonism has been diffused. It's so peaceful, it's a damned near dull."

"The meeting has been nuts-and-bolts -- convention-planning, that sort of thing," agreed Bill Lenker, a national committeeman from South Dakota. "There hasn't been any presidential hard sell this time around. When the choice was Ford or Reagan, head-to-head, with an incumbent in the White House, there was a lot of bitterness. But now there's a feeling of unity and even optimism. All we're thinking about is winning in November."

So much for the old policical truism that the party of incumbency goes into battle unified, while the Outs fight like cats and dogs -- or in the Republicans' case, like liberal elephants and conservative mastodans. This year, it's the Democrats who occupy the White House and are suffering the long knives of intraparty civil war. For the Republicans -- judging from the sweetness-and-light that suffused RNC Chairman, Bill Brock's Friday-evening social -- nonincumbency has apparently been cool salve on old party wounds.

At least, at National Committee gatherings.

"If you're looking for blood-stains, you won't find them here," said one western state chairman when asked whether all was as harmonious as it seemed. "Head out to Iowa or New Hamphire."

It was a movable buffet, catered on five floors, and the several hundred RNC members, and their guests mingled amid the desks and computers, as well as the food-and-drink-stocked conference rooms, of the recently dedicated new wing. Scheduled to run between 5 and 7 p.m., the good party feeling went on well past 9 o'clock, when the last bus left, returning committee members to the meeting site at the Capitol Hilton.

On the fourth floor, which featured a string band, open bar and "champagne desserts" of cheese, fruit and cake, Perry Hooper, an Alabama national committee man, was telling how it was back home in Birmingham and Montgomery.

"You might not believe this, but I've yet to hear anybody say they don't like a candidate," Hooper allowed. "Everybody's got a leaning one way or another -- but as of now, our March 11 primary is wide open. Whoever shows up well in the early primaries can take it.

"My son, you know, went out for football at a school where 91 others went out," said Hooper. "I told him, 'Son, if you plan to do any playing, you better do something to attract your coach's attention.' That's the way it is with Republicans this year. Whichever candidate attracts our attention most will do the playing next fall."

"No, nobody's tried to pressure me since I've been here," said state chairman Chester Upham, a Texas-size oil and gas executive from Mineral Wells who was more interested in talking about "Carter's god-awful energy policy" than his presidential preference. "As far as I can tell, there's been little or no presidentail politicking at the meeting," Upham continued, "but regardless, I'm strictly neutral Reagan, Connally, Bush -- they all have loyal followings back home. I'll tell you this, though -- whoever we nominate, the key to winning is an energy program that makes it as profitable to drill for oil in this country as it is in Libya."

Upham's wife, Virginia, a member of the Texas state executive committee, nodded in agreement. "We Republicans really don't have much to fight over this year," she added. "We're all interested in winning, and any of our candidates can beat either Carter or Kennedy."

According to one RNC source, however, there was a certain amount of national-ticket politicking at a different level."

"Bill Brock is campaigning for vice president," confided a committeeman, "to the extent that anybody actually campaigns for vice president. Some of Jessee Helms' people have been around, too, dropping word that their man's available. And Guy Vander Jagt [the Michigan representative, head of the House Republican campaign committee], he's another one running for it."

But Brock, it was pointed out, is from Tennessee, and if Howard Baker, another Tennesseean, is the party's presidental nominee, that would exclude the RNC chairman from being No. 2 man on the ticket.

"It would at that," was the reply. "But I really don't think Bill's concerned about that, if you know what I mean. There's no love lost between Brock, and Baker, none at all."

In another part of the room, Clark Reed of Mississippi, like Nofziger a scarred but still uninhibited veteran of the '76 Ford-Reagan civil war, offered a pragmatist's explanation of why presidential campaign activity was limited at this year's winter RNC session.

"With 80 percent of the convention delegates in Detroit being picked in primaries under the new rules, there's not too much this crowd can do for a candidate," said Reed, one of four Republican Committee regional vice- chairmen. "Reagan's folks had a hospitality suite open Thursday night, and Jim Baker and Wyatt Stewart have been glad-handing in the corridors, showing the flag for Bush and Baker, but nobody's hustling nobody. Not here, not now."

Buttons: On measure of the intensity of a political gathering is the number of campaign buttons adorning lapels, ties and blouses. By actual count -- not including an Agnew-Eagleton worn by one guest feeling no political pain -- there were only four buttons on display around "champagne dessert" tables. One Connally. One Bush. One Baker. And one Goldwater-Miller.

Jack Emmons, the New Mexico state chairman wearing the Goldwater-Miller, was asked whether his insignia reflected personal nostalgia or political conviction.

"both," he replied amiably, "We're all looking back and looking ahead at the same time. I think it's a case of the country catching up to where the party was in 1964."

"Yes, indeed, we're all among friends," Paul Arneson was saying in the ecumenical spirit of the evening "Have I been approached by any candidate? Well, yes, as a matter of fact. Baker's people and one or two others have talked to me about coming aboard. But . . .

"For me, at least, the 1980 campaign is more or less history," said the ertswhile campaign manager of the year's early Republican presidential dropouts with a shrug. "Here, have one. We've got a big supply."

He handed over a button, white lettering on deep blue, with the historical message: Senator Larry Pressler for President.'

It was anything but a hustle.