The seat they show must have been a pre production model. They do not come with a backrest or slot.
We are selling a lot of those seats and actually put one on our own F6B in the picture below.
We have a lot of them on order with Mustang and it is taking us a few weeks to get them.
They are a great seat for this bike and worth the wait. I have put a couple thousand miles on mine already.
If ordering from us make sure to use the discount code "seat4percent" to get the extra discount. Mustang Tripper Fastback Seats, Honda Gold Wing F6B