As abad said, depends on the organizer.
In my case, I allow 2-piece leather suit zipped up together no problem, but not textile-based jackets or suits. I've seen the damage even a slow abrasion crash can do to a textile jacket. I also don't allow flip-up helmets, I've also seen what a slow fall can cause, if the helmet happens to open on contact with the ground or wasn't securely locked ...

.
Make sure you don't save up too much on safety equipment, because once you ride on a track, you'll be coming back for more

., and if you happen to have a small fall for some reason, you don't want to blame yourself for not making sure you were correctly protected.
Good luck, and enjoy your time at the track ! Don't forget to come back and post about your trackday !
Mario Sobral