well, if you got the gold edition from the creator's site, he/she tells what is new/changed/fixed in the gold edition. it's basically the same as the pre-gold edition, except the octobreeder event is added in and maybe some other stuff, and most of the prior bugs had been fixed.
I think probably most people are using the new gold edition.
so the difference in the walkthrough must be simply between the normal game and the new game + (the re-playing of the game). many of things probably are only in the new game +, it seems.
if you ever played Chrono Trigger, it has a very similar new game "+", where you replay the game with all of your equipment (except the story line equipment), and you're able to go to the final boss and beat the game whenever you want in order to get the different bonus/extra 13 or so endings.