OK i have a couple of original NI packs first one is as designed with a few extras ( water hose retainer, useful c clip (glove and extra holder) and the normal climbing shackle),
The other has had some changes to it, cut off the belt, bungee cord added to the rear tapes, extra bungee cord/ elastic tapes on top for roll mat retainer. water hose retainer clip, small zip marker (glows for 10 years), climbing shackle added.
A few guys take off the side pouches and either put zips down the edges to fit plce side pockets, or tapes for molle kit, or mess pouches for small extras, some put a pouch on the rear for holding a basha (wet or dry) similar to the one seen here on this link :
https://www.dragonsupplies.co.uk/catalogue/770-Multicam-Commanders-Patrol-Pack or this :
https://www.dragonsupplies.co.uk/catalogue/1063-Titan-Bergen-Tan also some guys put normal webbing pouches on their packs such as the water bottle ones, that you can also see in those links. hope that helps