[Fictions]

I would have to say having a shop that is formally laid out would not be necessary to change. I believe this rule applies more to people updating their buy/sell list in further pages.
I could be very wrong on this issue though, but you should be fine so long as the front page is clear and kept up to date.
Edit: at worst you might want to state in the first post that the items you are buying/selling are located in the posts below or something.