Call it cowboy chic at the Old White House corral: red bandanas and candlelight, crystal goblets and Indian corn centerpieces, barbecued beef and fresh raspberries and cream.

The host wore his $1,000 patent leather Tony Lama cowboy boots with the presidential seal; his guests from the other end of Pennsylvania Avenue wore their Capitol Hill neckties.

"I was a little surprised," said President Reagan, looking cowboyesque only from his boots down -- the rest of him was in black trousers, a snappy green plaid sportscoat and a fire-engine red turtle-neck sweater, "but I thought finally I could go somewhere without a necktie. Then I came here and everybody looked like lawyers from the East."

And last night almost everybody did, with nearly 500 guests sipping two California wines and sitting on little gold chairs set up under a gleaming white tent on the South Lawn for the first in a series of White House salutes to the 50 state congressional delegations. With the host a Californian and his political pardner, George Bush, a Texan, nobody seemed the least surprised that the first two states to be so saluted would be their own.

Neither did anybody seem much surprised that the party coincided with a new round of budget cuts coming up in the old Hill corral.

"It was just a quiet soft sell. He was being a nice, gracious host," drawled Rep. Jack Brooks (D-Tex.), among the cowboy-booted Texans invited to share the president's table.

Did the "soft sell" work? a reporter asked. Was Brooks sold?

"On what?" asked Brooks, chairman of the House Government Operations committee, starting to feign suspicion.

"On what he's trying to sell."

"What's he sellin'? He didn't say. I didn't buy nothin'. I didn't get no deed. He didn't sign it, and when I buy," said Brooks, "he's gotta sign the deed."

"He could have a hundred parties, and it wouldn't mean I'd vote with him. There's no way I'm going to vote for deferrals in Social Security cost of living," said Rep. Matthew J. Rinaldo of New Jersey, ranking Republican on the select committee on aging. "I don't pledge blind loyalty."

Rinaldo said he and Vice President Bush flew to New Jersey for a fund-raiser earlier in the day and that Bush "said he didn't know what the president may come out with tomorrow" in his nationally televised speech outlining his decisions on further budget cuts.

"I think he's going to surprise a few people and go ahead in ways the rumor-makers don't understand yet," said Rep. George V. Hansen (R-Idaho). "I'm a pretty strong supporter of Mr. Reagan. And if he doesn't take any 90-degree angles I'll probably be with him."

Not everybody was going for his gun. Rep. John L. Burton (D-Calif.), sporting a Mao cap with a Red Army pin, reached for his spitballs and sent some sailing into the coiffeur of an unidentified woman guest.

"I was trying to get McGrath to calm down. He was raising hell," Burton said later.

Rep. Raymond J. McGrath (R-N.Y.) looked shocked at such an accusation.

"Nobody," he grumbled, "raises more hell than Burton."

Sen. S.I. Hayakawa (R-Calif.) never took off his Scottish plaid tam, making him easily the most identifiable Californian at President and Mrs. Reagan's table.

Afterward Hayakawa said he and Reagan never once discussed politics, not even the possibility that Maureen Reagan might be throwing her own cap into the California senate race next year.

"Doesn't bother me a bit," Hayakawa said, grinning. "The more the merrier."

On stage were the Statler Brothers, the country-western singers from Staunton, Va. "Darned good at that, for easterners," said President Reagan, who brought in some westerners as volunteer chefs for the evening. ("In California," Reagan explained, "we have people who do this for a hobby.")

Out in the audience were those who remembered barbecues of bygone days at the old Carter corral, when they drank wine out of plastic glasses, ate ribs with their fingers and sat at wooden picnic tables under the stars.

Said Peggy Stanton, wife of Rep. J. William Stanton (R-Ohio): "I'm a little surprised that we're not in blue jeans."