Tom Shales' preview ("Television's Vietnam . . . ," Style, June 26) of the Accuracy in Media film replying to the PBS 13-part series on Vietnam reveals more about his own prejudices than it does about the merits of the AIM documentary.

He starts off with a sneering reference to the AIM documentary as a potentially "hot ticket" that might be eagerly screened by those already partial to its "politically conservative" approach. This amounts to condemnation of AIM's documentary on the basis of guilt by association and not on the basis of its merits. Shales seems to imply that, since the producers of the PBS series are not "conservative," their version of the history of the Vietnam War must be superior to AIM's. The truth of AIM's critique of the PBS series is not Shales' primary concern.

What is most outrageous and irresponsible, however, is Shales' statement that "a smattering of supposed experts, including a couple of silly congressmen and some disgruntled Vietnamese now living in the United States, are paraded by to dispute this or that point made in the original 13-part PBS series." Actually, within the limits of a one-hour documentary, and without the resources available to PBS, Accuracy in Media made every effort to find and present some of the outstanding scholars of Vietnamese history and culture. These are experts recognized in the academic world by all scholars, liberal or conservative. Thus, Shales fails to point out AIM's inclusion of Stephen Morris, a professor at the Institute of East Asian Studies, University of California; Douglas Pike, of the University of California, one of the outstanding anthorities on the Vietcong; and Elbridge Durbrow, former ambassador to Vietnam, a Foreign Service officer with intimate knowledge of the events in Cambodia and Laos covered by the documentary.

Accuracy in Media's critique of the PBS documentary deserves a more serious review than the frivolous remarks of Tom Shales.