Yes, that article pretty much sums up the most common way of converting F180 to E975, even though I took a different route, which was easier and made more sense to me (but I am in the minority here, along with a few other people)... You can also find all this information here on XDA, plus, a lot of useful discussions about all sorts of different problems some people are having after the conversion, most common one being a weak or lost signal. Again, before you decide to go ahead with it, I would recommend to do some reading on XDA OG forums. If you go for it, make sure you do every possible backup (especially EFS) before starting to mess with your phone, so you can revert back to where you started, if you need to, without a major screw-up... Good luck!
Oh, BTW -- the article you referenced doesn't mention one important part. Technically, it's optional, but at least you should know about it. Optimus G (any model) has a locked bootloader. So, if you ever want to flash a custom recovery, or a custom ROM (or any unsigned zip, for that matter), or to do Nandroid backups, etc., you need to unlock the bootloader first -- rooting alone won't do the trick. "There is an app for that". (c)
Look up FreeGee on Play Store. Again, read about it here on XDA -- the process has been described in details. Good place to start would be a great FAQ thread by
@kimitza; you can take it from there.