Matt Wilson and Craig Kimber stated (http://errors.comics.org/show_bug.cgi?id=3951):
Cover not painted by Matt Wilson. It is erroneously stated in the issue that Matt Wilson painted it.
Despite the disclaimer above wherein Matt Wilson supposedly denied having painted the cover for this issue, the original art bears his signature (obscured by the UPC symbol) and the cover art itself is stylistically identical the his body of work, which strongly indicates that the painting is actually his work. Perhaps he simply forgot which cover he might not have provided for this series when the statement was made.