Neil,
no it doesn't come preped.
also before you start check the lugs underneath thet are about the size of a 5p piece and are evenly spaced roughly at the edge of the h/l brake light. One of mine hase come loose and will need bonding in and re-spraying when i can be arsed to get it into the bodyshop.
i think they might be mounting points as done on the cup racers (not sure) but i'd make sure they're bonded in properly before you spray it.
best of luck mate don't worry if it looks like it's a poor colour match it's the way this LY changes colour it took me a while to relise it was ok
Max