Last October, Mr. Littler said, he packed the 1787 Margaux in a tennis bag, flew to Kennedy International Airport, handed the bottle to Mr. Sokolin, turned around and flew back to England.

An importer and distributor, who did not want to be identified, said he had told Mr. Sokolin that ''if it comes to pass that he can sell the wine'' he would provide paper work that showed that the wine had been properly imported, that ''12 cents in Federal duties and taxes'' had been paid and that other Federal and state requirements had been satisifed.

The D. Sokolin Company, which Mr. Sokolin owns, first advertised it for $250,000 and then $394,000 before raising the cost to $519,750. He said he had only two serious queries from customers. Will the state authority investigate? ''We don't comment on that,'' Mr. Chernela said, ''but you can draw a logical inference. He didn't sell it, so there is an open question of whether he did violate the law.''

Hardy Rodenstock, a wealthy West German wine collector, said in 1985 that he had purchased a cache of more than a dozen bottles of Bordeaux labeled with the initials Th. J. that were found in a Paris cellar. But many wine fanciers are dubious because has no one has proved that the wines were Jefferson's.

That skepticism has outlasted assurances by Michael Broadbent, the wine director at Christie's in London, that experts at the auction house had established the age of the wine and that Jefferson probably owned a 1787 Lafite. The skepticism has also outlasted the purchase of that bottle by the family of the publisher Malcolm Forbes, who paid $156,450 for it at Christie's in 1985. The purported cache contained at least three bottles of Margaux. ''I don't know of anybody who has had any,'' Mr. Broadbent said. He recalled that a bottle of 1787 Mouton had cracked while being opened at the estate about two years ago. The wine was quickly decanted and drunk. ''It was delicious.'' Mr. Littler said Whitwhams, convinced the 1787 Margaux was genuine, had purchased it from Mr. Rodenstock, whose agent delivered it by hand from a vault in Monte Carlo, Monaco. Its February 1988 catalogue listed it at $75,000; the price rose to $212,000 in the September catalogue.

For the last nine years, the Four Seasons has given a banquet to mark the arrival of successive Bordeaux vintages in the United States. The formal debut of the '86 vintage was marked at Sunday's black-tie $250-a-ticket 17-wine seven-course dinner.

The focus was the '86 Margaux, arguably the chateau's greatest since new owners took over in 1978 and rehabilitated the estate's sagging reputation. Margaux is one of the five so-called first growths, the top wines, in the Medoc as classified in 1855.