Help me to choose firmware?

Hi to all. I am from Serbia, and i am trying to downgrade my lumia from wp8.1 to wp8.0
I cant find product code of my phone so i dont know which firmware to download :confused:
On my phone box i can only find these:
nokia920.1
imei:356355056988668
wlan:2847aa9576b7
material:0023g07
CV AL MK RS-(Republic Serbia)
black
fcc id: pyram-821

Please help! :(

from xda-developers http://ift.tt/2cxakwu
via IFTTT