The Lone Ranger, seated atop his white horse Silver, whirled around, looked the camera in the eye, mask and all, and yelled "Hi-yo, Siilverrr!" That's when the audience went nuts -- applauding, whistling, screaming. And this was in the Kennedy Center's Eisenhower Theater, a room full of California and Washington notables -- many of whom are more used to pin strips than fringed leather vests and cowboy shirts. But there they were, sprouting up all over at the premier of "The Legend of the Lone Ranger."

There was Reagan friend and businessman William Wilson in an enormous black-brimmed suede hat and black suede suit. ("The hat is a Charro. It really means Mexican horseman.")

Sitting next to him was Attorney General William French Smith in suede jacket and string tie. Then there was Washingtonian Oatsie Charles in full Indian headdress, calmly puffing on a cigarette.

And not too far from them was the urban cowboy himself, Aaron Latham -- the man who wrote the story on which the movie "Urban Cowboy" was based -- taking it all in his scuffed-up cowboy boots.

Jack Wrather, co-producer of the movie and producer of last night's extravaganza at the Kennedy Center, was right. "We just thought that Washington didn't have too many western affairs," said Wrather in Stetson and string tie with turquoise clasp.

But then, Michael Horse, who plays Tonto in the movie, was right, too, when he smiled and looked around and summed it all up with, "Oh, I think this is pretty silly."

No matter, Washington loved it. Republicans -- of the Nofziger, Schweiker, Smith ilk -- showed up along with Wrather's California friends -- of the Alfred and Betsy Bloomingdale, Bob Six and wife Audrey Meadows, William Wilson ilk. President Reagan sent a tape-recorded message saying he was sorry he couldn't be there for the celebration of the West.

There were even a few Democrats for seasoning. Like Jody Powell, former Carter press secretary, in new western shirt. (But not new jeans, he stressed.) "Now that blue jeans are chic . . ." he said grinning. "We wore 'em all those years and felt bad about it. Now we find out they're as in as tassle loafers."

A lot of brand new jeans and cow boy boots and Stetsons last night. Some on backwards, probably. But definitely on, during the barbeque after the movie in the Atrium of the Kennedy Center. There was much hovering around the buffet tables laden with barbecued beef, pinto beans, Wick Fowler's Two-Alarm Chili and brownies.

The L.R. himself, Klinton Spilsbury, was there -- without mask or hat, but with his mother and father and five brothers and sisters.

"You've got a winner," said Justin Dart, California businessman and Reagan friend, pumping Wrather's hand.

Willow Evans, Michael Horse's girlfriend, not unexpectedly loved his portrayal of Tonto. "You get to adore him for an hour and a half," said Evans, who was wearing a low-cut blue velvet halter dress -- and turquoise, of course. "When I first saw him I thought 'Oh my god, that's my boyfriend? Hmmm . . .'"

Some went western all the way -- like Californians Dick and Joan Stevens (he is president of Wrather Hotels) who were each wearing $6,000 worth of doeskin leather, beads, rabbit fur and so many bells you knew when they were walking by.

But you didn't need to go very western at all -- just chic. Like Betsy Bloomingdale in flounced black silk and lots of gold bead jewelry. "This is as western as I get," she said.