If its a forgery,
its a good one.
The provenience itself is interesting:
http://hiddencodex.com/images/The_histo ... exico6.pdf
But I myself can not tell if its real, or Mixtec or Tarascan (P'erhepechuan), or a forgery.
There is also the problem of seeing whatever is left of its verso (other side), which will likely involve hyper-spectral imaging.