I've looked for a way to edit the primary defense and offense stat of armors and guns and I've found the values. It seems that unique items (purple) won't persist the stat cross saves however the regular items do.
I've managed to link the dmg/def lists to the Item Editor offsets so they can be found under WeaponsOnly and ArmorOnly sub sections. Some armors have multiple so I've added 6 slot offsets and 2 for guns, ignore the extras if your edited item does not have them.
The weapon dmg list offsets need a bit of cleaning and of course it might need more testing...
the general structure for armor is:
and for guns:
int: min dmg
int: max dmg