Hi Mael! Thank you again!
I managed to do it yesterday, I will leave it here just in case someone else is interested:
in item_randomopt_db.txt, I've included a line in the end:
RDMOPT_NONE,{}
in item_randomopt_group.txt, for each group, I've set:
RDMOPTG_OHStaff,1,RDMOPT_NONE,0,0
in const.txt, I've set:
RDMOPT_NONE 194
Server-side that is it. You are gonna receive a warning when (re)starting the server but that doesnt seem to cause any harm.
On the client-side, I had to change two files:
On addrandomoptionnametable.lub , before the last line:
[EnumVAR.NONE[1]] = "A classic equipment.",
and on enunvar.lub, again before the last line, add:
NONE = {194, 0},
That is it! You now have a chance to have items with no extra "buffs" at all along with the buffed ones.
biali's post in Random Option System to include original drops (with no extra script attached) was marked as the answer