Less than one week after issuing its "final" hostage proposals, Iran has revised them. On the face of it, the change makes things worse in a crucial aspect. From demanding that the United States post $24 billion in guarantees against return of the hostages, the Iranians now ask $9 billion in frozen assets be returned forthwith and the rest of the claims worked out. Only then would the hostages be freed.

There is, however, another aspect to the change. The Iranians presented the revision quickly, even hastily, and in evident response to the broad and bitter rejection of its earlier proposal by the administration, Gov. Reagan and the American people as a whole. Has it begun to dawn on Iran that to let the matter extend past Jan. 20 is the court a further delay, and perhaps a tougher American bargaining position? Interesting.

From the Iranian point of view, the virtue of the new proposal is that it would let Iran get its hands on at least some of the money in dispute at once. wThis raises the question of whether Iran is not feeling the triple economic pinch of the chaos of its revolution, the sanctions organized by Washington and the damage incurred in its continuing war with Iraq. Also interesting.

There has been a discernible change in the last week on the American side, too -- not so much in the official negotiating approach as in popular feeling. Most Americans seem to have had a strong reaction to Iran's demand for, in effect, $24 billion in ransom.Gov. Reagan almost certainly spoke for the nation when he said: "I think all of us deep down inside have an anger . . . at the idea that [the hostages'] captors today are still making demands on us for their return, when their captors are no better than criminals and kidnappers."

The Iranians then added insult to injury by bringing the 52 prisoners before cameras (and foreign diplomats) for holiday showing. Perhaps the Iranians thought this was the way to make American people pant, and pay, for their speedy return. Actually, most people appear to have been sickened further by the Iranian's cynicism in trying to fence publicly their stolen wares. There is a grimness and a determination in the country now.The Iranians should not overlook it.