It's entirely possible for the helicopter to crash land and be survivable, basically. 

Incidentally, 1967, not a lot of SAMs in South Vietnam. That's North Vietnam's air defense grid, which is ferocious terribad and only gets more sophisticated as the Vietnamese gain experience in using the SA-2. But the SA-2 is huge and not man portable. 12.7 and 23mm AA guns are definitely not ruled out, however.

This will be a concern when my pilot character gets involved as flying Sandy for a CSAR operation.  (A-1E escort for rescue choppers)