US media conflated the NFL, PRG, VWP (in South Vietnam) and PLAF (all anglicised acronyms, of course).  US media tended to distinguish the DRVN and PAVN, but often conflated the DRVN and VWP (in the DRVN).  Due to this conflation, Viet Cong is used commonly in English to refer to the PLAF, NFL/NLF/FLN, VWP and PRG.  And yes, I'm very aware of the current VWP line on all of the Southern revolutionary organs being front organisations—they're producing a whig history to invalidate the role of the buddhists, cults, democratic bourgeois nationalists, and local revolutionaries in the national liberation struggle.