The photographer could be of any nationality as several wore US Jungle Fatigues because they were so easy to acquire. I see one problem with the photographer figure, though. He lacks a cargo pocket on the right leg.

It's worth pointing out here that if you're looking for these products at Firestorm you'll need to look under the Callsign Label, not the Firestorm Brand

Jeez, you Seppos, everything's about you...
Given that the Firestorm figures are produced in Australia, there is good reason to suppose the 'correspondent' figure is meant to represent an Aussie journalist, of which there were many in SVN.
A close examination of the pictures of the figure shows that the 'fatigue' jacket is not a US type, and probably meant to represent the old 'bush jacket' type of garment - these later morphed into the polyester Safari Suit of the early 70s, nice...
These bush jackets were popular items either brought over from Australia (ex-military) or made by tailors somewhere in SE Asia - given that many reporters may have cycled through other Commonwealth countries where there was both an Australian presence and a British influence on private purchase jungle clothing (eg, Singapore, Malaysia), this is not an unreasonable assumption to make.
Look at the pocket detail and the epaulettes.
As to the trousers, these represent the Aussie Jungle Green trousers, now refered to by collectors as 'early' or 'first' pattern - modelled after Battledress trousers, these had one large pocket on the left thigh; the later style had one pocket per thigh and were of a slightly different cut.
If that's too much analysis for a 1/35th scale figure, well, too bad - I think Firestorm are to be congratulated for going the extra distance to make this figure that bit different.

regards
acav

(I do know that Seppo is a derogatory term directed at Americans).