I'm putting my few skills at Japanese at work, but I'm far from being fluent, so don't expect a very reliable translation.
大乱闘スマッシュブラザーズ 大乱戦BOOK!!
Here just says the name of the game and something that sounds like a strategy book.
注目の3DSソフト「スマブラ」の すべてのキャラと すべてのステージを 別冊ふろくでとこっとん大攻略川
予習バッチリで 発売を待てるゾ
Here, it first mentions about the 3DS version.
These caught my attention:
すべてのキャラと すべてのステージ - This means: "All characters and all stages."
From what I can understand, it does seem that all characters and stages will be shown on a separate special issue of the magazine.
Besides that, it says something like being prepared for the game's release.
Note that this is a very loose translation. I had to use a dictionary in some parts and my Japanese is far from being fluent, but this should be a general gist of what is written.
@
Venus of the Desert Bloom
will likely provide a better and clearer translation.