the star probably stands for different kit parts in the same box. your KT kit might have Kit 'X' parts aswell.
Or, alternatively, I'm completely wrong, and Tamiya just likes stars.
Anywho, unfortunately, since only 50 porsche turrets types were produced, every one would have zim. BUT, don't worry about it. I didn't put zim on mine, i don't think it's a big deal, just build for fun.
Remember, all of you: This is our art medium. While others use pen and paper, we use paint and plastic. Therefore, we are all given a little artistic license when it comes to finishing the final product.
And that, dear modelers, is TacoBuff's deep thought for the day.