Unknown PACT Respirator - Possible GM38 clone

I got this mask off of eBay on a bid and it was advertised as a NATO mask.
It turns out its most likely a PACT mask due to the filter and writing inside of the mask.
AZ or A2 is stamped on the forehead of the mask and inside is stamped 1982.
The mask appears to be a GM38 style mask covered in a canvas like material, any info on the mask would be appreciated.