It isn't completely possible to determine if this is a forgery or not as the paper can't be evaluated from the scan. According to the Persiphila catalogue, the genuine stamps of this issue are typographed and the forgeries are lithographed.
The catalogue further mentions that forgeries have two lines above the word "Postes" in the lower left and genuine stamps only one line. The Persiphila catalogue does not show a perforation error like this in the list of errors and varieties for these issues. The set has five major stamps and minor numbers for differing colors. Good luck.
Try contacting Behruz Nassre, he is active on the Iran Philatelic Study Circle group on Facebook. He likely won't be able to give you a definitive opinion from a scan, but could certainly tell you if it's worth pursuing a cert.