I recently came across a battlepack of ammo and am needing some help with the headstamp.  The boxes are labelled:

20
Round
7,62x51mm
Ball
FNM 82-25 (nato cross)

Headstamp is FNM 82-25 with nato cross at top.

Cartridgecollectors.org lists 3 manufacturers for this headstamp:

FNM Fábrica Nacional de Municiones, Santa Fe, México (near Mexico City)
FNM Fábrica Nacional de Munições de Armas Ligeiras, Chelas, Portugal
FNM Unknown Factory, Mexico

Is there any way to determine if this is Mexican vs. Portugese?  If it is Mexican, has anybody had experience with or heard anything negative about it?  It will be used in a FAL.

Thanks.

ETA:  It's a green vinyl battlepack if that helps.

Sounds like Portuguese .

I have a case here and the battle packs are dark green ,
head stamped  FNM which I believe stands for :

Farbica Nacional Militar = Portuguese

Sounds like PORT...works fine in my AR10.

Thanks for the help!