The battle was held in Sa Pa, North Vietnam. So the armies must be the PAVN (not NLF) and some special forces of ARVN or US. The NLF only fought in the South. I hope you change your map again. Plus, the Sa Pa is the only place in Vietnam that has snow and so it attracted a lot of tourist for its special. It has several French-ish buildings and many high moutains. Add it!