Hi Bill,
I am wondering whether this has anything to do with the naming of Tombaks..........
".....Tombac, as spelled in French, or Tombak is a brass alloy with high copper content and 5-20% zinc content..............The term tombak derives from the Javanese derived Indonesian (erroneously termed Malay) word tembaga- meaning copper. Tembaga entered Dutch usage concurrent with their colonisation of Indonesia (see Dutch East Indies). Likely, the term was used generically to describe Indonesian high-copper brass items, including gamelan gongs. It is one of the very few Indonesian or Malay loan words used in English, German or Dutch.
http://en.wikipedia.org/wiki/Tombac
Perhaps, its simply due to brass decoration
Kind Regards David