I had a look at the other link, and the NSN is most likely 8465-17-707-2566. Only the last 8 digits show, but the rest can be deduced by the stock class (8465 is pouches) and the country identifier code is most likely 17 which is for the Netherlands. So the NSN is not original to the pouches, as a Cdn pouch would have the country identifier 21. Yes I know the other pouch linked is wartime and pre-dates the NSN system, but when the NSN system was adopted by Canada, numbers were assigned to any existing stocks.
So all that said, I am at a dead end for the above NATO number. My resources do not cover that number, and a google search does not bring it up.