In Step 25 of the instructions of this kit, you are told to attach Part B66 to the turret roof. In reality this is the cover for a periscope; the periscope itself is a clear part, F2, which you attach underneath the roof.
But the real Tiger "Tiki" didn't have a periscope here. To represent "Tiki" better, you should omit these parts and fill the holes.
The other decal option, Tiger "231", did have a periscope. But its cover was narrower than the kit part, and it had parallel sides, not tapered sides.