Duplicating pages but making them independent


I am currently making a website that has a Tierlist for the best in slot items for each Champion which changes every 14th day. My problem is that I would like to make a type of gallery that stores all the old pages with best in slot items so that if a person would like to use those items later he would be able to go back and look at it. So I copy the pages and call them “Best in slot item champion 1 Version 1.1”.

The problem is that if I would like to make changes to the design later on, the old pages change with, because the classes are the same and i’m not going the duplicate every single class on every page. Is there a way to lock a page or something similar.

Here is my site Read-Only: LINK