The Pentagon decision to give veteran status to civilians who served as merchant seamen during World War II could mean greater job protection and higher pension benefits for the newly designated veterans who later worked in civil service jobs.

On Wednesday, the Defense Department announced plans to consider as veterans men who served on U.S.-flagged merchant ships between Dec. 7, 1941, and Aug. 15, 1945. Most of the 250,000 who served on merchant ships during that period are dead. But thousands are still alive and an unknown number -- including several who called this column yesterday -- later joined the government as civilian employees.

Under federal job rules military veterans get some added protection during layoffs. Veterans can also count their military time as civil service time, thereby making them eligible for larger annuities that are based on a combination of salary and length of service.

Federal officials said yesterday it will be up to the Veterans Adminstration and the Office of Personnel Management to decide what effect, if any, the new policy will have on civil service job and retirement rules.

As a first step, persons covered by the new policy should get a discharge certificate from the military branch they served as civilians. Applications, which must be made on Form 2168, should be addressed to one of these:

Commandant (GMVP-1/12), U.S. Coast Guard, Washington, D.C. 20593-0001.

Commander, U.S. Army Reserve, PAS-EENC, 9700 Page Blvd., St. Louis, Mo., 63132-5000, or,

Naval Military Personnel Command (NMPC-3), Navy Department, Washington, D.C., 20370-5300.Playing the Market

Starting this month workers in the Federal Employees Retirement System have two new tax-deferred investment options: a stock and a bond fund. Tomorrow on WNTR radio (1050 AM) Tom Trabucco of the Federal Thrift Investment Board will talk about the new options and answer calls from listeners.Picking a President

The 200,000 members of the National Association of Letter Carriers are voting -- by mail -- for their favorite presidential candidates. The January issue of NALC's magazine contains a postage-paid ballot listing Democratic and Republican candidates. Democrat Gary Hart reentered too late to get on the ballot, but there is a place for write-ins.

Four years ago Sen. John Glenn (D-Ohio) won the postal preference vote. Though it didn't deliver him the White House, it also didn't hurt NALC interests on Capitol Hill. Glenn did become chairman of the Governmental Affairs Committee that controls most postal legislation in the Senate.What's In a Name?

A 20-day suspension if you use the wrong one on your boss, that's what! A Navy civilian learned that lesson the hard way after drawing the punishment for publicly calling his boss an "anti-Semite," a "Nazi" and several other things. His appeal to the Federal Labor Relations Authority was rejected after he admitted making the remarks in a loud voice before coworkers and having previously received a written reprimand for the same behavior. Had he been a TV sportscaster he might have been fired.