At $38,000 a year, the typical Washington federal worker has to wonder who lives in the stately homes of Potomac, Great Falls and Georgetown and who can handle the payments on the $50,000 car in the next lane.

Part of the answer is in the current issue of National Journal magazine. It lists the pay and perks of some of the 300 trade and professional association executives here. Many of them are former high-ranking government officials.

Next month career federal executive pay will crack the six-figure barrier. Top Senior Executive Service pay goes to $108,300 a year, thanks to a much bigger raise than the 4.1 percent that will go to lower-level federal workers. But even the new SES big bucks look puny beside some association pay.

For example:

The head of the Smokeless Tobacco Council gets $257,000 per year, plus another $30,000 in benefits and allowances, according to the magazine.

The president of the American Association of Advertising Agencies gets $251,855 per year.

The president of the American Gas Association is paid $376,447, plus benefits.

Salaries of $300,000 are typical for key association executives.

Some former U.S. officials have done well. Jack Valenti (a special assistant to President Lyndon B. Johnson) is listed at $672,500 as head of the Motion Picture Association of America; John R. Block (former agriculture secretary) receives $270,000 as president of the National American Wholesale Grocers Association; and Richard Schweiker (former senator from Pennsylvania) makes $473,000 as head of the American Council of Life Insurance.

The list shows there is financial life after government service. But it helps to leave as a top White House aide, senator or Cabinet officer. Bonus Holiday Update

Still no word from the White House about the possibility of a Christmas Eve holiday. It would be a welcome gift to workers. And local merchants would love the extra shopping day. In 1986 workers got Friday, Dec. 26, off. But in 1984 they did not get Monday, Dec. 24 off.

The president is under no obligation to grant the bonus day. Nor is there any deadline for announcing a decision. But it would be nice -- for transportation officials, merchants and federal workers -- if the White House would end the suspense. Meanwhile, the Supreme Court has announced its 350 employees will get Monday off with pay. Half Century Club

Walter Wilson begins his 51st year with the government today. He's been with Fort Belvoir's night vision lab for the last four decades. And he obviously likes his job. NARFE Downsizing

The National Association of Retired Federal Employees is facing a headquarters shake-up. As many as 20 of NARFE's nearly 90 staff jobs could be downgraded or eliminated within the next few weeks. With half a million members, NARFE is easily the biggest of the federal-postal organizations. But its dues are the lowest of any organization in the nation. Its national dues are $12 per year and are set to rise to $15 next year.