Font Name vs. Font Style. BUG?

I have found what appears to be an inconsistency in: "fonts.cache-1" files:

Arial Narrow Bold (TrueType):

     "arialnb.ttf" 0 "Arial Narrow:style=Bold ... "

Helvetica Narrow Bold (Type1):

     "hvnb____.pfb" 0 "Helvetica:style=Narrow Bold ... "

I have looked into this a little and it does appear that the above 
information results in a correct reading of the information in the font files.

I'm not certain which is correct (I would choose the second [Helvetica]), 
but the point is that they are different and any system that uses 
FontConfig to get this information: FamilyName and Style is going to have 
to be able to handle two different schemes.

So, the question is: is this a BUG?

If so, should FontConfig parse the first one so that it is the same form as 
the second? or vice versa?

--
JRT