Russ Thurman, technical adviser on Home Box Office's "Vietnam War Story" trilogy that is airing tonight, is unique.  He hasn't yet written his book about the Marine grunts he knew during the war.
    But two friends from Vietnam days have.  A third is writing a screenplay about the war.  Therein lies a story within a story told in a Vietnam novel that became the basis for Stanley Kubrick's film, Full Metal Jacket.
    The novel, The Short-Timers, is by former Marine combat correspondent Gustav Hasford, who shares screenplay credit with Kubrick and Michael Herr for Full Metal Jacket.
    Hasford's book has an insider's salute of sorts to the others in his Marine unit--Thurman included--who reported on the war and, on more than one occasion, joined it.  They're in the novel as characters, all grunts.
    Guys like Bob Bayer, now a copy editor for The Times, as Mr. Short-round, a platoon leader.  And Mike Stokey, now writing Tet, a screenplay.  He's Stoke the Supergrunt.
    The best-known of the cast:  Dale Dye, adviser and actor in the Oscar-winning Platoon.  Dye also is author of Run Between the Raindrops, which, like Hasford's book and Stokey's script, centers on the Marines' costly month-long battle for Hue after the Communist command's Tet Offensive in January, 1968.
    He's Daddy D.A. in The Short-Timers.
    Thurman rounds out the ensemble in Hasford's novel as a hard-core sergeant called T.H.E. Rock.
    Such is the closeness and kinship of war, which for Thurman and a lot of others, has continued long after Vietnam.
    It's how he wound up earlier this year at a film location on a plantation outside Savannah, GA., advising actors and extras how to play Marine riflemen in one chapter of HBO's "War Story."  Dye hired him for the job.
    Although Thurman wryly recalls that he and a brash young corporal named Dye had a fist fight after first meeting in Da Nang in 1967, he's Dye's closest friend now, and was best man at his wedding in 1983.
    Their Marine careers parallel.  Like Dye, he was a "mustang" officer and began his career as an enlisted man.  Each received Purple Hearts for wounds in Vietnam, each served 21 years in the Corps and each retired as a captain.
    A wiry, intense man of 40, born in Utah and now living in Vista near San Diego, Thurman didn't plan to get into show business after retiring in 1985.  He set up shop as a media consultant and also planned to write.  But Dye urged him to try film work.
    Thurman's debut was with "War Story," as the newest member of Dye's "Warriors Inc.," a Sepulveda-based company that provides technical advice on military movies.
    He has seen Platoon.  But he's not among those veterans who found fault with the Oliver Stone film.  It's just one man's Vietnam movie, not the ultimate Vietnam movie, he said.
    "I think there was a lot of intensity in Platoon that tended to disguise or overpower what was my Vietnam--the kinship, the brotherhood.  That's my Vietnam," Thurman explained.
    "Sure, I remember the brutalities of the war.  But there was some of that kinship I remember in Platoon.  It's just that because of the intensity of the movie, a lot of people didn't come away with that."
    Viewers, he said, probably will be more aware of the closeness of which he speaks when they see the three separate dramas filmed in Savannah for "Vietnam War Story."
    One is set in combat, another in a bar-brothel patronized at night by GIs and before dawn by the Viet Cong, and the last--in which Thurman has a bit part as a Marine brigadier general--in a stateside Navy hospital.
    "Brotherhood is very strong in war," he said.  "That's the only thing you've got."
    Despite the different types of stories filmed for HBO, he said, "the pure essence of all three of them is that brotherhood."
    He grinned when kidded for not having a Vietnam book or screenplay written, like his First Marine Division mates Hasford, Dye and Stokey.  He'll get around to his own book someday, he said.  But it may not be just about the war.
    It may be about his years in the Marine Corps, which in addition to Vietnam has taken him just about everywhere, from Norway to Australia and even Egypt.
    "The Marine Corps is a study in contrasts," he said.  "There's a tremendous love-hate relationship you have for it.  Fortunately, I think there's always more love than hate.  But boy"--he grinned--"it sure doesn't show at times."
    Thurman, who covered the Vietnam war in 1967 for Marine publications, was on hand for the end of the war in April, 1975.  But not as a combat correspondent.
    He wasn't allowed into the country in that capacity, he said, so he wangled his way in as a radio operator in a rifle company, flown in as part of a Marine contingent to help guard the Americans and South Vietnamese being evacuated from Saigon in the last few days of the war.
    Shortly before the city fell to North Vietnamese troops, his unit was pulled out and flown by helicopter to a Navy carrier off the coast of South Vietnam.  Thinking of writing about the experience, he got a friend to tape radio transmissions of the last Marine helicopters flying back from Saigon.
    He didn't hear the tape--which he still has--for several days.  He was so exhausted that he just slept or sat around numbed, he said.
    When he finally heard the tape--heard the confirmation that the last helicopter was outbound--it was heartbreaking.
    "I'm not at all afraid to admit that I cry," he said.  "And I cried then.  Not for Vietnam.  I wish I could say it was for Vietnam.
    "But it was just for sheer frustration, the guys who had been there, died there, for the 'why' of it.  Nobody likes to think that what they've done has been for nothing.  I guess maybe it was that, the frustration."
    At what point do you finally put Vietnam behind, walk away from it?
    "You never do," Thurman said.  "You never do."