Followers of developments in South Africa learn not to count reforms before they hatch. But unless the government is guilty of some unfathomably stupid deceit, the abolition of the "pass laws" announced this week must be taken as a development of major significance.

We are not, to be sure, witnessing the final collapse of apartheid, but the laws the goverment says it will repeal next month (and which it says it has already stopped enforcing) have been among the more oppressive features of black life in South Africa.

You get a sense of the significance of the newest reform from the fact that literally millions of blacks have been arrested for pass law violations, some 160,000 in 1984 alone. At least 245 blacks were either serving sentences or awaiting trial on pass law violations at the time of the government announcement. They have all been freed, a spokesman said.

The pass laws have been used to restrict the movement of blacks within South Africa, determining where they may travel, where they may live, where they may look for work. These laws, says the announcement, are dead. So are those that forbid blacks even to seek court relief against forced removal from certain residential areas, that define "idle and undesirable" blacks, and that put harsh limits on the employment and housing for blacks.

But if blacks will be far freer to travel and seek work under the new dispensation, they are still subject to the Group Areas Act, the system that assigns every acre of the country for residence by a single ethnic group, with nonwhites frequently required to relocate on short notice when a particularly desirable piece of geography is reclassified.

Nor does the new policy yet apply to citizens of the so-called independent homelands.

There is ground for caution even beyond these shortcomings. First is the fact that earlier "reforms," announced with great fanfare, have turned out to be either nullities or else mere adjustments of the outer edges of apartheid: for instance, the parliamentary reforms of a few years ago (which gave limited rights to Asians and mixed-race South Africans but none to blacks) and the more recent repeal of the mixed-marriages laws.

The more significant caution is that the newest reforms, which undoubtedly would have been hailed by blacks as recently as three or four years ago, may turn out to be too little too late to quell the violence that has wracked the country. Already, black militants and even the moderate Bishop Desmond Tutu are saying the changes have come too late to make any difference.

A relatively short time ago, the government could have bought the peace necessary for evolutionary change by seriously improving so-called Bantu education, moving toward equal employment opportunity and establishing some form of black political participation (for instance, granting self-government to the black townships). But the reforms not taken when they would have mattered quickly turn out not to matter.

Now the demands, so uniform as to constitute a new black orthodoxy, are for full and undifferentiated citizenship, a total dismantling of apartheid and one-man/one-vote. A government that could have had evolution has, by its reluctance to introduce real change, made revolution an acceptable idea.

And the result is that repeal of the pass laws -- by any measure a real reform -- may turn out to be of no more significance than the repeal of the mixed-marriages act.

I hope that the government will continue to take serious steps toward reform, and that it will be taken seriously by those on whose behalf the reforms are undertaken, because the alternative -- bloody revolution in which there might well be no winners -- is too awful to contemplate.

I hope it, but I'm no longer sure I actually expect it.