Possibly a stupid question, but of she’s Viet Cong, where did she get what appears to me as a US built rifle?

EDIT: Derp, i forgot they could capture US-supplied south vietnamese equipment. Let my question be a warning to you all about remembering to think before you hit that submit button.

This is Lam Thi Dep, a 24 year old, twice widowed Viet Cong soldier.

https://rarehistoricalphotos.com/female-viet-cong-guerrila-1972/