The shock/spring assembly comes off very easyly and as one piece, just need to lift the bike so that the rear tire is supported by the ground and the bike is supported by the jack, and the shock unit will slide right off. BUT, most plate and brake light units I've seen mount on the outside of teh shock stud, if this is true with the one you have, then you won't even need to raise the bike or remove the shock. The shock sit on "Studs" and then have a Bolt and Washer to keep it from sliding off.
Hope this answeres your question
