YES, you can get what you want on your 3LZ Z06!!!
The above chart shows that you can get competition seats in black without any microfiber suede black inserts. It is option code # 195. You would also need to order AE4 to get your comp seats.
You order will therefore include (no cost/standard/automatically) NK4: Steering wheel, 3-spoke leather-wrapped, flat bottom.
If you do those three things, you will have a complete leather seats and a complete leather steering wheel.
You do NOT want option 196, for that would change your seats from all leather to having sueded microfiber insets! You also do not want to add option N26, for that adds the alcantara steering wheel and shift knob.