It's just a prefix if I'm not mistaken. Nice note you got there triggersmob - I don't think it's an easy note to find.
As well as, I don't think most Modern Asian notes use such numbering system anymore. In the past, Malaysia and Singapore used to do that but both don't do that any longer, perhaps because it's just too difficult to read.
My partial coin collection
http://www.omnicoin.com/collection/gxseriesMy numismatics articles and collection:
http://www.gxseries.com/numis/numis_index.htmRegularly updated at least once a month.