Ah, good thinking 
I tried searching on Google in English and in Japanese, but the latter mostly seemed to bring up NicoNico results that didn’t seem all too conclusive.
Like you say, since people took photos of it it seems like it’d be legitimate, but if anybody here could confirm it 100%, that would be cool. Photoshopping seems fairly unlikely, unless they have a SECRET TAKEHITO CONSPIRACY TO SPREAD INTO THE WORLD???
(Or not, haha.)
