they never actually scrutineer you anyway.As long as nothing is hanging off, you will be fine.
If its a road bike, tape up the lights and remove the mirrors (or turn them in).
Go over the bike and make sure that everything is tight, oil the chain, drop tyre pressures (on a 600, usually 28 rear and 30/31 front)
Apart from that just relax, dont forget to breath and dont be shy to ask for advice from the instructors...thats what they are there for.
Enjoy the day, once you start you'll be hooked!!