"Many of my Bali blades have a gonjo from pure iron (just black) while the blade have pamor."
I don't think this indictes that they are made of a different quality iron, just a part that contains no pamor. This was done in some cases, as i understand it, to hide any clues of what pamor your blade had for others while you blade was sheathed. It seems to me that most old Bali blades are like this so when i see a Bali blade described as old that does have pamor on the gonjo i am immediately suspicious.
