Material quality connection 1 (EF025618) == CuZn21Si3P --> Material connection 1 (EF025616) == ??

We've got fittings (EC003024) that are made of gunmetal.
Material quality connection 1 (EF025618): EV016521 - CuZn21Si3P (CW724R) 
Material quality connection 1 (EF025618): EV016520 - CuZn21Si3P (CC768S)

Since I can't find gunmetal for Material connection 1 (EF025616), what's the relevant material to use?
1) EV000138 Copper
2) EV000154 Other

Second, do you agree that raising an RFC to get 'gunmetal' added to EF025616 (et al.) would be a good thing?

Thanks very much!

As far as I can judge, gunmetal is a brass alloy, so that would mean Material would be Brass (few others say bronze alloy?). 

A clear and unambiguous listing of materials and material qualities is always challenging. Bronze and brass are both alloys containing copper, but since commonly known and distinguishable in the market accepted as Material. So I would choose Brass instead of Copper in your case? 

You can't generally say if Gunmetal is acceptable as value for EF025616, that depends on the other values in the list, that can be different for each class. The list has to be unambiguous and 'of the same level'. My estimation is that it will NOT be admissible together with brass and bronze in the same list.