Question Regarding Schweser Notes

I apologize if this is a stupid question, I did try to search for an answer before posting.

I have signed up for the level I exam and was planning on using my books from 2010 to study for this test. But after doing some research and coming to the conclusion that this test is likely harder than I anticipated, I decided that putting myself at any sort of disadvantage was probably not smart.

So I was hoping to buy some used books online and save a couple of hundred bucks. My question revolves around the fact that some of the books I am seeing are green and some of them are blue…but both say Kaplan Schweser. The books I bought in 2010 are green and the ones on the schweser website are green, is there some kind of difference? Are the blue ones a knock off or just the same thing in a different color?