Not grey, dunkelgelb or RAL 7028, your base color in extinguisher. Dunkelgrau was standard until February '43. Looks like but cannot tell for sure you have small rear idler wheel, single monocular site in mantlet. There were 2 40mm roofs, a 2 piece and 1 piece. Both used King Tiger loader's hatch. I think it was around May '44 that they got the grenade launcher in the turret roof too.