Not quite sure what you mean - "conscious choice". I've been using the same green mix for armour on several different miniatures and like it so used it again.
What I meant was that these miniatures look exactly like the Martian Marines from Doom (original games), with the green armour, visored helmets and bare arms:
(Although I must have forced myself to forget about those bare abs, even back in the nineties; I had no recollection of those
)
I thought maybe the client was going for a not-Doom vibe with these...