Looking at the photo's I think the Vickers MG is retained. On photo's of this aircraft when it was still in it's original livery but already impounded one can see a single Lewis gun mounted overhead.
You sure got me curious on this one. I did just one Dutch WWI aircraft so far (the F2b 1:48 scale by Eduard). Although I really like to build Dutch aircraft I really focus on WW2 for this lot. As far as WW1 concerns I prefer versions of the actual country.
Good luck building and we probably speak to each other in Nieuwegein (for all your people who do not understand Dutch; this is a bit of a strange name for a city, cause translated direclty it means: "Newfun"; believe me the city itself is hardly any fun at all!)