I remember seeing someone here posting a green KLu marked belt some time ago too, questioning why it was green, was that also you?
It's probably because in the early 80's the M78 uniforms started to be move more to an actual green color. Before the M78 the uniforms were really grey, early M78's were grey too, but slightly different.
From about 1983 onwards lots of uniform parts are actually grey-green.
Last weekend I saw a shirt with a cardboard tag attached, even calling it jacket, field, green.
I've seen photos from even later, mid-90's, where a green belt is worn with a standard KL canteen.
So fieldgear probably went green during the 80's too.
And about the BB marked belt, it's 100% the same as many KLu belts that also don't have suspender buckles, meant for dress occasions. Last weekend I dug through a box with dozens of them, while just needing 1 with actual buckles, because I only have one without.