Try dividing up the sentence like this: [It says so] [right on the spine]. "It says so" means that it says that it's a classic. The word 'so' refers back to the previous sentence and represents the statement 'It's a classic'. The adverbial phrase 'right on the spine' tells us where this information is printed. The word 'right' indicates that it's in a very clear, accessible and obvious place.

You've made a mistake. You should write "It means" not "it' s mean".

it' s mean так правильно