EARLY Saturday morning, opponents of the Chilean military coup set off a bomb in International Telephone and Telegraph's New York City office. The "Weather Underground," an offspring of the old Weatherman group, claimed responsibility for the action. No one was hurt by the explosion, in which several ITT offices and facilities were damaged.

ITT tried to create economic chaos and civil war in Chile three years ago, in order to defend its telephone equipment from expropriation by the new socialist government of Salvador Allende. After Allende's victory in 1970, ITT and its friends in Washington -- friends already predisposed toward large American corporations and entirely captivated by ITT's illegal gifts to President Nixon's re-election campaign -- supported those trying to overthrow Allende's Popular Unity government.

Now that the Chilean army has overthrown Allende and seized power, all indications are that ITT, if it wants to, will return to Chile with new guarantees against expropriation.

Saturday's bombers, despite all their precautions, could not be certain that innocent people would not be injured in the explosion. And clearly, the bombing did not save even a single Chilean liberty or a Chilean freedom fighter. For this reason, the legitimacy of the bombing, at the very least, is highly questionable.

But if it was not certain in advance, it is certain in retrospect that the bomb destroyed only some of the resources of a corporation fomenting repression and violence on a huge scale, and hurt no one. In retrospect, therefore, if Saturday's bombing makes ITT's managers think twice before their next foray into international politics, it is no cause for sadness.