It had everything expected in a beauty pageant--flashy production numbers, a swimsuit competition and even the inimitable pageant host of hosts, Bert Parks. But the shapely legs parading down the runway were rather hirsute and the winner made his triumphant runway march in a tuxedo instead of a gown. Capturing U.S. Man of the Year honors in Atlantic City, N.J., was Mr. Missouri, William Billings Jr. of St. Charles, in a contest billed as a "role model" pageant. "We feel men should be role models other than Rambo," Parks said. The 30-year-old Billings is a hospital management specialist who provides hospitals with programs to combat drug and alcohol abuse. He and the other contestants competed in tuxedo, leisure wear and swimsuit divisions--boxer-style. And, instead of a talent division, contestants were asked to respond verbally to how they would handle an "everyday life situation." First runner-up was Mr. California, Mark L. Harris, 24, a Modesto contractor. Second runner-up was Mr. Arizona, William A. Fritsch, 30, a Mesa model. Mr. Nevada, Larry Stevens, 25, a Las Vegas sales representative, was third runner-up. "The first thing I'm going to do is celebrate with the other 50 guys," Billings said. "Then I'm going back home to find out how much work is on my desk." Among the winner's prizes were five one-week resort vacations, a designer tuxedo and a gold diamond ring.