Sure I read mirrors off with my outfit but I've seen vids of their sessions with mirrors on
Red, I have done quite a few track days with no limits, great company by the way, and I am pretty sure its no mirrors. I definitely do not remember seeing any mirrors but I could be mistaken.
To be honest I would recommend taking them off or taping them up, as well as taping up your lights and speedo. Simple reasons, as PG has said, they are unwanted distractions. The road rider in you will keep looking in the mirrors and down at your speedo, as much as you will tell yourself you wont, trust me you will. If you cant see out of your mirrors or what speed you doing you will be more relaxed and concentrating on the track in front of you, which is the important thing. Only worry about what is in front of you, those who want to pass will make the choice where to do it, its not your place to get out of their way.
The lights thing is just good track etiquette, for me there is nothing worse than someone with their brake lights visible. It puts me off my own braking markers as road instinct kicks in and tells you if the guy in front is braking then you should, even though I know I can brake a good bit further on.
Hope you don't mind me putting my tuppence worth in here, ultimately you want to have a smooth relaxed fun day, these things will help that to happen.
Which circuit are you attending?