One guy jumps on it and takes the blast and saves his three buddies. The answer matters. You'd feel cheated if it never happened. Without the grounding reality, it's just a trite bit of puffery, pure Hollywood, untrue in the way all such stories are untrue. Yet even if it did happen - and maybe it did, anything's possible even then you know it can't be true, because a true war story does not depend upon that kind of truth.
Absolute occurrence is irrelevant.
A grenade sails out. One guy jumps on it and takes the blast, but it's a killer grenade and everybody dies anyway. That's a true story that never happened. Twenty years later, I can still see the sunlight on Curt Lemon's face. I can see him turning, looking back at Rat Kiley, then he laughed and took that curious half step from shade into sunlight, his face brown and shining, and when his foot touched down, in that instant, he must've thought it was the sunlight that was killing him.