If past performances are any indication, the finals of the George Mason University High School Invitational Saturday should be an accurate barometer for the rest of the indoor track season.

The first major track meet of 1985 in the Washington metropolitan area has traditionally been a competitive event. And the GMU meet (which begins at 1 p.m.) should again be a class showing of the area's track and field talent. The trials were held on Dec. 19-20, and the best performances in each event on each day were combined for the finals.

While the meet is non-scoring for the teams, there are plenty of individual matchups to keep any track enthusiast interested during the 26-event schedule. The meet will begin with the 55-meter hurdles and the girls shot put. The last two races, the boys and girls 1,600-meter relay, are scheduled for 5:30 p.m.

Last year, Patrick Mann, a Gar-Field senior now at Georgetown University, set a national high school indoor record of one minute 3.32 seconds in the 500-meter dash.

The races to watch this year are the boys and girls hurdles. Ronald Jones of H.D. Woodson qualified with a time of 7.6 seconds, but Tony Watt of Gar-Field, Bart Bailey of Suitland and Lyle Decker and Jeremy Worrell of Stuart are only .10 off the pace.

The girls hurdles features Lynda Tolbert of Ballou, who set a metropolitan-area best of 7.93 at the Episcopal Invitational Dec. 15, then came back five days later to run the best qualifying time of 8.2 in the event.

Tolbert will defend her title against Gracie Brown of McKinley and Christelle Williams of Lee, both .10 behind, in a race that could produce another area best.

While the winning time of the boys 500 may not be a national record, the race is sure to be as close as last year. William Lumpkin of Anacostia was sixth last year and leads the rest with a qualifying best of 1:05.4. Robert Bailey (1:06) of Largo and Terrance Shepard (1:06.5) of Eleanor Roosevelt are ranked next.

The boys 55-meter dash is packed with sprinters who have run 6.4 or better. Rod Scott of Friendly is favored based on his 6.3 trials time. But Bren Lowery of T.C. Williams, Erwin Mathews of Friendly, Jim Scott of Oakton, Ron Schaefer of Mount Vernon and John Lord of Chantilly have all run 6.4.

Eric Metcalf of O'Connell missed the trials because of a death in his family, but meet director Norm Gordon has allowed Metcalf to compete in the dash, 300 meters and long jump based on his previous performances this season. Last year, Metcalf won the dash in 6.42 and long jump in 22 feet 7 inches .

The 1,600-meter run should be easily won by Kirk Young of Central. The Maryland Class A cross country champion placed fifth here last year and recorded a 4:18.5 in the trials this year. Bill Boatright of Annandale ran 4:26.9 in the qualifiers after placing runner-up in the Episcopal meet with a 4:31.9 mile.

The 3,200 should be a much tighter race with Virginia cross country champion Kevin Ryan of Kempsville and Steve Dupree of Langley posting 9:31.3 and 9:32.4, respectively. The 1,000 should also be close, with Thomas Boggan of T.C. Williams a bit ahead of the field with a 2:37.4.

The competition to watch in the field events is the third meeting this year between Irwin Grant of Warren County and Chris Lockett of Woodbridge in the pole vault. Lockett beat Grant with a 13-6 on fewer misses at Episcopal, but Grant vaulted 14-0 to Lockett's 13-6 at the trials.

The only question that remains for Metcalf in the long jump is can he move up any higher on the nation's all-time high school indoor list. He is tied for the seventh longest jump ever after a 24-7 3/4 at Episcopal.

Worrell and John Rymiszewski of Mount Vernon comfortably lead the triple jump and shot put fields, respectively. Worrell, runner-up last year, jumped 47-9, more than a foot ahead of the next best jump. Rymiszewski won the shot last year, and has thrown 53-7 1/2.

The best girls performer could be Lake Braddock junior Cathron Birge, who is ranked first in the 300 and 500. Birge ran 1:16.3 in the trials of the 500, and she will defend her title against Kelli Roberts of Central, who ran 1:16.9. In the 300, Birge is more than a second ahead of her competition with a 40.4 effort. Charlene Hinton (41.8) of Jefferson-Huguenot-Wythe and Roberts (42.0) follow.

Hinton qualified No. 1 in the dash at 7.0, clearly ahead of LaVerne Williams of Edison, Sonora Clark of Oxon Hill and Christine Ahearn of McLean, all at 7.2.

Ashley Riggs of Severna Park has the edge in the 1,000 after posting a 3:03.5. Aimee Harms of Annandale and Jenny Montgomery of Langley are two seconds back.

The 1,600 should be a close race, but the 3,200 will not. Beth Jacobson of Kennedy and Kathy Graves of South Lakes lead the 1,600 with 5:08.4 and 5:09.6, respectively. Erin Keogh of Langley, the Virginia cross country champion, ran 10:43 at the 3,200 trials.

In the field events, Tolbert, Christelle Williams and Carmen Mann of Falls Church have long jumped better than 18 feet. Ginny Hanlon of Sherwood and Amy Ellis of Crossland cleared 5-5 and 5-3, respectively, in the high jump, while Mann has gone 5-2, five inches lower than last year's winning jump. Jean Burris of Mount Vernon should beat Tracie Mines of Suitland in the shot put.