I got that image from
Siliconera, a site that's very reliable. While it is sketchy that image hasn't appeared anywhere (even Target's own website) else, and has a foreign langauge, I do have a few reasons to believe it is real. Reason #1 happens to be the
press release Konami released yesterday, they specifically mention 4 Collector's Editions (would've been nice for them to list them off), which we know 3:
Toys"R"US - Vulcan Horuseus 145D
BestBuy - Ultimate Gravity Destroyer Stamina GB145S
General - Bakushin Susanow 90WF
So what's the forth Collector's Edition? This one.
Reason #2 to believe it's real: The ESRB logo on the packaging indicates this is a North American release, not a European or Australian release (where there are Target stores IIRC). The fact it's called "Metal Masters" instead of "Nightmare Rex" is equally strong.
Lastly, Reason #3: Siliconera isn't going to make a fake box art, especially for this game. They often receive press packages with assets (images, videos, etc.) and that's likely where the image came from.