A dinner guest stared at the picture on my study wall. Obviously, he was impressed, because there I was with Henry Aaron, giving The Hammer hitting tips. At length, my dinner guest said, "That sports coat you've got on in this picture, is that what they were wearing in those days?"

Alas, I had already fed the bum. "I still wear that coat," I said.

"The stripes," he said, pointing at the coat's design and giggling. "I et it. If the referee doesn't show up for a basketball game, you just tuck your coat in and take his place."

Very funny.

Sartorial insults are turning my brown slacks blue. Trying to figure out where my money goes, I sat down with a financial consultant the other day and he asked, "How much do you spend on clothes a month?"

Being honest, I said, "I bought a pair of tennis shoes last spring."

"But doesn't your job require you to wear any certain kinds of clothes?"

"Just this," I said, spreading my arms.

His threepiece, $300 suit recoiled at the sight: brown slacks that almost reached my ankles, a short-sleeved shirt with an alligator on the chest and a wide, black belt that might have been stolen off a baseball uniform. It was a stroke of good fortune that I wasn't wearing my windbreaker with the permanent wrinkles (six months in a golf bag and you'd wrinkle, too).

"Causal?" the comedienne said.

"Very," I said.

And that night, in a listing of the best-dressed media folks in town, Washington magazine came to "best-dressed sportswriter."

"No award," the magazine said.

Verrry funny.

I suppose I should be dealing with Something Important. The future of Western civilization seems to hang on the Redskins making the playoffs. So I hope they make it. The Bullets are going great and that's nice, but we have to remember the season doesn't end until we're old people. The Caps?

Let's talk about my stripped coat.

It's a nice coat.

I wore it every day for six weeks in Europe in 1972.

My wife will tell you that.

"If I ever see that coat again," she said then, "I'll burn it with you in it."

Shes a nonviolent person most of the time, so I tell her to turn her back whenever I'm leaving the house in that coat.

The coat is famous.

In Texas Stadium, Dan Lauck of Newsday, a sportswriter whose wardrobe runs to corduory cutoffs, called my name across the press box and tugged at his shirt sleeve.

I had no idea what he meant.

"The coat," he said loudly, "Where is it?"

That day I was wearing my blue suit coat. It's normally saved for special occasions, such as funerals and interviews with Ann Margaret.

"Wise guy sportswriter," I said to Lauck.

It's not the fault of sportswriters they dress that way.

Would you spend $300 for a three-piece suit to interview John Madden?

And mustard.

Have you ever dripped mustard from an RFK hot dog onto a $20 tie?

And hazardous duty, Walter Cronkite may look spiffy, but he's never had to worry about Jimmy Carter throwing him in the shower or dousing him with champagne after winning an election. Sportswriters, in the line of duty, often must sacrifice their threads to get the story.

I looked around The Post sports department the other day. The tennis writer arrived wearing a Greek fisherman's cap. The baseball man's tweed hat had the crumpled brim turned down all the way around, as if Reggie Jackson had molested it. The layout man came in in brown jogging shoes.

All right, so Bill Blass would be horrified and Gentlemen's Quarterly wouldn't allow us to buy their magazine.

It doesn't matter. We need only heed the advice of that old sportswriter, Hank Thoreau. He once looked upon the gaudy uniforms of the Walden Pond Pirates and said, "Beware of all enterprises that require new clothes." And Isaac Watts, a scribe from an earlier day, expressed the futility of such costumery. "Let me be dress'd fine as I will, flies, worms and flowers exceed me still."

I will, however, buy another pair of tennis shoes next spring.