WHATEVER ITS domestic or foreign policy problems, the Reagan administration is certain to leave office with a reputation for philatelic flair.

The Postal Service last week unexpectedly added four more issues to the current year, bringing the 1987 total to a near-record 109 stamps and commemorative postcards, and this week disclosed that 1987, the administration's final year, may include almost as many stamps.

There were no plans for another 50-subject sheet of commemoratives in 1988 to follow this year's best-selling wildlife set.

Even so, 1988 promises a number of multi-color "topicals," as collectors call them, plus about 40 new "regulars." (The smaller, non-commemorative regulars will come automatically if the postal service gets its long- expected rate increase next year.)

On the topical side, there will be a set of four commemoratives honoring cats ("America's favorite household pets," the postal service says), four featuring carousel animals, eight for 200th anniversaries of states, four for Antarctic explorers, and five featuring classic antique cars, plus winter and summer Olympics stamps.

Several of the 1988 stamps will have a special appeal to Washington-area collectors. Virginia and Maryland each will get stamps for their states' bicentennials. Virginia's Admiral Richard Byrd will be honored in the polar explorers set and Washington's Blair House will be featured in a commemorative postcard.

Other 1988 commemoratives planned include ones honoring legendary Notre Dame football coach Knute Rockne, golfer Francis Ouimet, showman Buffalo "Wild Bill" Cody and civil rights leader James Weldon Johnson, author of the song "Lift Every Voice."

But don't write 1987 off. No sooner had the number of new stamps and cards this year hit 105 than did the Postal Service hurriedly add four more menu items.

The lastest additions include a new 10-cent definitive in the Great American Series, a commemorative postcard and two more coil stamps in the popular transportation series that's featured antique vehicles and boats.

The 10-cent stamp honors Red Cloud, the Sioux indian chief, and will be issued August 15 in the Nebraska town that bears his name. The stamp, 38th in the Great American series that serves as one of the Postal Service's regular stamp series, will be printed in red, of course.

Robert Anderson of Lexington, Mass. based his design on Smithsonian Institution photographs of the chieftain of the Oglala Sioux. Red Cloud, well known for his protests over the slaughter of the buffalo on the plains, is the third Indian in the Great American series, following Crazy Horse on a 13-cent issue and a 19-cent Sequoyah release.

The Red Cloud stamp will replace a 1982 stamp in the series honoring the late Sen. Richard Russell (D-Ga.). The postal service said reprinting the Russell stamp would've required a new perforation and plate numbers -- "almost like" creating a new stamp. And since the service has a number of approved "Great Americans" on the shelf for quick issue, officials decided to place Red Cloud on the presses at the Bureau of Engraving and Printing.

The new transportation series stamps, issued in coils mostly for bulk mailers, will include a new five-cent stamp featuring an antique milk wagon and a 17.5-cent stamp featuring the Marmon Wasp, the first car to win the Indianapolis 500.

Both the milk wagon and racing car stamps will debut September 25 in Indianapolis during the INDYPEX '87 stamp show.

The 17.5-cent stamp, a new denomination, is the rate for mailers who qualify for discounts by using the nine-digit ZIP codes. The five-cent milk wagon stamp will be a replacement for a 1913-style motorcycle stamp that the service decided to replace because the press on which it was printed four years ago is no longer in use.

The final new postal item is a "Take Pride in America" postcard to be issued September 22 in Jackson, Wyoming.

Collectors seeking Red Cloud first-day cancellations should send, by September 14, envelopes bearing the stamp plus at least 12 cents more postage to meet the first-class requirement to Customer-Affixed Envelopes, Red Cloud Stamps, Red Cloud, NE 68970-9991. The postal service will affix the two Red Cloud stamps and one 2-cent stamp for those who send envelopes and 22 cents to Red Cloud Stamps, Red Cloud, NE 68970-9992. Or for 30 cents each, collectors can obtain covers with three of the new stamps.

Bill McAllister is a member of The Post's national staff.