Nos. 77-1948, 77-1977. Argued January 8, 1979. Decided April 11, 1979. Angelo V. Arcadipane, Washington, D.C., with whom William W. Osborne, Jr., Washington, D.C., was on brief, for petitioner in No. 77-1948. Hiram S. Grossman, Flint, Mich., for petitioners in No. 77-1977 and intervenors in No. 77-1948. David F. Zorensky, Atty., N.L.R.B., Washington, D.C., with whom John S. Irving, Gen. Counsel, Carl L. Taylor, Associate Gen. Counsel, Elliott Moore, Deputy Associate Gen. Counsel, and William R. Stewart