You know, one of the great ironies of Rifts is that the stuff folks would actually use in the average group isn't depicted at all (not including Triax 2). The civilian and paramilitary market of "normal-ish" vehicles is woefully unsung. The Bog Boss and the Mountaineer were among my favorite pictures in the old Main book.
All that to say, thanks for bringing such a quality picture to the game.
It's not intended for NGR use and in fact is banned from the NGR for it's military potential. My take on a RRK Super-Armored Hover Truck from page 85 of Triax 2; quote: "...The potential for abuse with such a heavy-armored vehicle is high...It is illegal within the boarders of the NGR."
So to avoid too much trouble with the government, RRK deliberately does not paint a camo pattern on the vehicle, but does offer Forest Green, which of course is a great base for a camo pattern.
Why green?..because the post-post-apocalyptic world where you'd find this hover truck is 90% wilderness, and in the northern climes where this particular truck is found, it's largely forest. Hence, forest green.