GToys Blog bought a copy of Good Press June issue to check out if there's any information of this kit, and found out that the box art shown was meant to introduce the process of creating the package design for MG Wing Gundam (already released) instead. The four box art of Wing Gundam Zero were shown as "Step 1".
Also, there were some text below of the box that reads "pose with rifle separated" and "reserve pose" (?).
GToys Blog commented that he's unclear whether the box art of Wing Gundam Zero were shown on purpose, or if it's a mistake. And so, it's of course not confirmed at the moment whether Bandai has indeed developed the model and is ready to announce it.
Good Press June issue was released on May 6th at 590 Yen (inclusive of tax).
Information is from GToys Blog. Image is from this previous posting.