Go for it!
You can make either a teardown (more entertaining, may gloss over some details) or a disassembly guide (a repair guide with the express purpose of fully taking something apart).
You may find there are differences between your process and the existing guide. Feel free to explicitly talk about those differences in the introduction to your guide.
Also, when writing your guide, you don't need to pretend the other guide doesn't exist. Feel free to reference the other one as needed, if you feel that your guide is lacking in instructions or images.
Best of luck!
