I was honestly unaware that anybody actually knew how the jetpack was painted, hence why it's debated so often. I've also most commonly seen them referred to as being gray, first I've actually seen of anyone saying they should be white. I also didn't mean to offend you, I'm almost always willing to be wrong.
I've gone through the images so much man, and they still look pretty gray to me. I think I'm also skeptical about being able to make it look right by doing it that way, but I'm willing to give it a shot for the sake of accuracy.