Federal workers thinking of retiring to pick up a pension cost-of-living adjustment that is bigger than their likely January pay raise are already out of luck.

Retirees are due a COLA of at least 4.1 percent. Some experts predict the actual January pension adjustment will be 5.2 percent or more, based on living cost trends. Either way, the COLA option looks better than the federal pay raise (either 3.6 percent or 4.1 percent) in the works.

Some federal employees, who are hypnotized by the pay versus COLA difference, are talking retirement.

Unfortunately for the would-be retirees, Congress has prorated the COLAs. The idea is to keep workers from retroactively cashing in on COLAs designed for retirees.

If an individual retired in early January of this year, that person is entitled to 11/12ths of the January 1991 COLA. People who retired early this month get 5/12ths of the COLA. Those who wait until November will get only 1/12th.Biting Issue

George Davis, health and safety director for the National Association of Letter Carriers, says nearly 3,000 postal workers -- mostly letter carriers -- were bitten by dogs last year. Some employees were mauled so badly they had to take disability retirement. The taxpayers ultimately pay most of their medical and retirement costs. Davis would like to see mayors and city councils adopt -- and enforce -- leash laws, even for dogs that "never" bite.Pentagon Travel Offer

The American Federation of Government Employees local No. 1092 expects a good turnout at its 5 p.m. Thursday meeting at the Pentagon. The door prize: two tickets to any city serviced by TWA. The local had about 400 members before word of the door prize spread. Since then, it has picked up a few more dues-payers. People

Kimberly C. Parker has joined Morrison Associates, a public policy consulting firm, as vice president. She handled legislation for the American Federation of Government Employees and the National Treasury Employees Union and worked for Rep. William H. Gray (D-Pa.). Jim Morrison, the firm's president, was the Office of Personnel Management's associate director for retirement insurance.

William Morgan got the Royal Institution of Naval Architects' gold medal last month in London. He heads the ship hydromechanics department at Navy's David Taylor Research Center, where he has worked for 39 years.

Roger R. Trask is the new president of the Society for History in the Federal Government. He's the General Accounting Office's chief historian.Investments

Workers next year can make unrestricted investments in the stock, bond or treasury options of their tax-deferred thrift savings plan. Starting in November, employees can earmark their biweekly contributions any way they want. Before, most of their contributions were limited to the treasury fund. In 1989, the C-Fund (stock) option paid 31.03 percent, the F-fund (bond) option paid 13.89 percent and the safer, government-guaranteed G-fund (treasury) option paid 8.81 percent. The plan is open only to active workers.