We had these invisible NVG mounted on our helmets in previous games. They magically appeared when we pressed N key and it was so unrealistic. In Arma 3 alpha, devs fixed this and we could see nice looking NVG mounted on our helmets when not in use. At that time, I was looking forward to the possible future addition of animation for clapping down NVG.
Now, in the current dev build, they are invisible again. I believe this is a bug, not an intentional 'rollback.' Please fix this.