I saw and handles about a zillion pairs of prismatic binos of the No2 and 5 types and worked as the sniper wing as a very young in service Armourer in the 60's and later when they came under the wing of the Small Arms School plus an Instrument Technician. And I never saw a pair of green covered or coloured binos either. If you wanted to change the colour or the texture you just wrapped them in old hessian or scrim net or an old face veil like everyone else......... Just as they still do

Mind you, I never saw a green Tele Sct Reg either. I just wonder if that particular one has had the brown covering washed with a material that has impregnated the covering material with a fluid with high penetrative qualities such as leather dye. As anyone who has dealt with government contracts will tell you. If you don't supply them with exactly what the contract says then it's the chop - at your cost!