2 paint questions

I airbrushed my 2001 wrc car Mica blue, Can I polish that or do I need to clearcoat it?

And I have painted my jtcc primera metallic green...I found out that it doesnt polish..heh..So do I need to clearcoat that? How would I polish them then? Or do you apply decals, clearcoat, then just leave as is?

Thanks

Any Tamiya Mica, Metallic or Pearl needs to be clear coated then polished.:)