This episode is se ton January 6th 1969. We gather this from episode 53 "Acceptable Losses" where Zeke is awarded the Distinguished Service Cross for the mission in this particular episode, the date mentioned is January 6, 1969.
"Booby traps acounted for 17 percent of all American wounds suffered in the Vietnam War."
Original UK airdate
LWT Saturday 21st March 1992 23.30