I'm 90% sure it is generated by the client. I'm not completely sure, but the other numbers (00001s) are the augment slots(even if they can't have augs). Someone's augs do show up on item links right? (I don't play live). The proper people to talk to really is the macroquest guys and see if they know of a hash/crc/whatever function that is called on the itemid+augs string or whatever. I never got an answer last time I asked.
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++[>++++++<-]>[<++++++>-]<.>++++[>+++++<-]>[<
+++++>-]<+.+++++++..+++.>>+++++[<++++++>-]<+
+.<<+++++++++++++++.>.+++.------.--------.>+.
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