Yep, it's real. I have also purchased cels from 
that seller before..... And this little beauty 
has cost me the "small fortune" of 80000 yens, 
now i cannot afford the other KOR cel that popped 
up for auction -_-.

As you say the background is non matching, i can 
tell. Don't even know if it's a background from 
the series or even a real background (the other 
cels that i got from him some time ago had laser 
copy backgrounds) and the auction doesn't mention 
if the background is real or not, at least as far 
as i can understand the translated text.