Even on our side of the world they are not common. As mentioned, the Army stopped ordering SWB at around this time, though a small number of Series 3 SWB have been found, so its not the very last Australian military 88".
As you have found, some of the later vehicles have the lights in the guards. The simplest restoration (once you get your "proof of age" examination) would be to have the front guards cut appropriately and swap the hinges for the correct 2a style. Then you would keep the "patina" AND have a visually correct vehicle. Plus you get to add your own layer to its history!
Still, parts for these are relatively easy to come by in Australia and you would have no trouble sourcing appropriate panels if you were prepared to pay shipping. Brush guard pattern is available through REMLR,or there are any number of them here, esp as you would want the later style. They were fitted to Series III military Land Rovers until the early 1980's.

