Junkyard dogs, that's what the Reagan administration said it wanted when it removed 15 inspectors general from office the day after it took over. But the White House threw a bone toward the departing IGs, saying it might rehire some of them to stand sentry in its battle against government waste and fraud.

With 12 of the 16 statutory IG posts filled, the administration has found five of the ousted IGs to have sufficiently fierce snarls, and has welcomed them back to the kennels.

Paul R. Boucher will stay on guard at the Small Business Administration and Charles L. Dempsey will remain at the Housing and Urban Development Department. Thomas F. McBride will move from the Agriculture Department to Labor and Frank S. Sato to the Environmental Protection Agency from the Department of Transportation. James B. Thomas, who was the IG for HUD under President Ford and later the director of the bureau of accounts at the Interstate Commerce Commission, was reappointed as the Education Department's chief waste-watcher.

Reagan also promoted some assistant IGs to top dog -- Joseph A. Sickon from assistant at HUD to IG at the General Services Administration and John Graziano from assistant at Commerce to IG at USDA. Most of the others have some junkyard experience as well: Robert L. Brown at the State Department was a senior inspector in the IG's office at State, and K. William O'Connor at the Community Services Administration had, in the Carter administration, executive oversight responsibility for the inspector general program.

The other nominees: Richard P. Kusserow, an Ex-FBI agent with expertise in the field of white-collar crime, named IG for Health and Human Services; Sherman Funk, a minority business specialist at the Department of Energy, named IG for Commerce, and Joseph Welsch, an official of the U.S. Railway Association, to run the IG office at Transportation.

That leaves unfilled the inspector general post at Interior, NASA, the VA and the Pentagon.