Four past Olympic medalists were among the gold-medalists at the U.S. National Greco-Roman Championships, held at the MGM Grand Garden Arena in Las Vegas, Nev., April 13-14.    Claiming the Outstanding Wrestler award was 2000 Olympic silver medalist Matt Lindland (Oregon City, Ore./Sunkist Kids) who claimed the 187.25 pound title.    Lindland moved up one weight class from last year, and defeated 2000 U.S. Olympic teammate Quincey Clark (Minneapolis, Minn./Minn. Storm), 4-3 in the gold-medal finals. Lindland, a past Pan American Games and World Cup champion, won his fifth U.S. Nationals title.    Two other medalists from the 2000 Olympic Games won U.S. Nationals titles: Garrett Lowney (Freedom, Wis./Minn. Storm) at 213.75 pounds and Rulon Gardner, (Afton, Wyo/Sunkist Kids) at 286 pounds.    Lowney, a bronze-medalist in Sydney, defeated Jason Loukides (Colorado Springs, Colo./U.S. Army), 3-1 in the finals. It was Lowney's first U.S. Nationals title.    Gardner, a 2000 Olympic champion, won his fourth career U.S. Nationals title with a 1-0 overtime referee's decision over Dremiel Byers (Colorado Springs, Colo/U.S. Army).    The other Olympic medalist on champion row as 1996 Olympic silver medalist Dennis Hall (Plover, Wis./Sunkist Kids) at 127.75 pounds. Hall defeated 2000 Olympian James Gruenwald (Colorado Springs, Colo./Sunkist Kids), 5-0 in the finals. It was a bit of revenge for Hall, who was beaten by Gruenwald in the 2000 Olympic Trials finals.    Another past Olympic who won a U.S. Nationals title was Kevin Bracken (Colorado Springs, Colo/New York AC) at 138.75 pounds. Bracken, who as fifth in the 2000 Sydney Games, beat James Shillow (Quantico, Va./Marines), 6-0 in the finals. It was his third U.S. Nationals crown.    Winning a second U.S. Nationals title was Keith Sieracki (Colorado Springs, Colo./U.S. Army) at 167.5 pounds. Sieracki defeated T.C. Dantzler (Colorado Springs, Colo./New York AC), 5-0 in the gold-medal match. Sieracki last won the U.S. Nationals in 1996.    First-time U.S. Nationals champions were Jeff Cervone (Colorado Springs, Colo./Air Force) at 119 pounds and Marcel Cooper (Quantico, Va./U.S. Marines) at 152 pounds.     Cervone beat two-time Olympian Shawn Sheldon (Colorado Springs, Colo./New York AC) in a 2-1 overtime referee's decision in the finals. Cooper stopped Steven Woods (Colorado Springs, Colo./U.S. Air Force), 2-0 in overtime in the finals.    The Most Falls award went to Darnell Lollis (Colorado Springs, Colo./New York AC), who pinned two in 1:52. The Div. I Greco-Roman team title went to the U.S. Army with 49 points, followed by the New York AC with 41 points. The Div. II Greco-Roman Teams  title went to the Sunkist Kids with 46 pts., followed by the U.S. Air Force with 23 points.