No. 74-1384. Argued February 26, 1975. Decided June 9, 1975. Fred W. Drogula, Washington, D.C., for appellants. Harry R. Silver, Atty., Dept. of Justice, with whom Carla A. Hills, Asst. Atty. Gen., New York City, Earl J. Silbert, U.S. Atty., Stephen F. Eilperin, Atty., Dept. of Justice and Stephen E. Alpern, Atty., U.S. Postal Service, were on the brief for appellee Klassen. Peter Carre, Atty., N.L.R.B., for appellee Nash. John S. Irving, Deputy Gen. Counsel, N.L.R.B., Patrick Hardin, Associate Gen