Yes... 'best' translates to 'only'.

You could use WWII U.S. Marines, but then you don't get 'the rifles and helmets are too big for these guys' look of the bulk of the ARVN and of course the figures are 'super-sized' in terms of height (okay all Vietnamese aren't vertically-challenged and all Americans aren't giants).
For me the '62-'65 period is far more interesting to game, but even if you wanted to go into the 'Mattel Rifle' era, the ARVN are definitely ignored by manufacturers.
