The Tiger had four large identical cooling fans inside its rear hull.
This photo gives a good idea of their colours and finish. The blades and the housing are aluminium or similar. The central disk and its nuts have a bronze-like colour. I don't yet know why those materials were used.
The kit's fans are slightly unrealistic in places, considering its scale.
The biggest inaccuracy is marked here : a gap between the fan unit and the back wall. In the real tank there was no gap at all, and in fact the fans would not work if there was a gap (the air would simply loop around).
If you want to open the rear grilles (which are hinged), the easiest fix for this is to remove the locating lug that sets the position of the radiator-fan unit. Place it farther to the rear so that it touches the back wall. For increased accuracy you could increase the thickness of this rear wall, which is not a scale 80mm.