ulCodePageRange1のsymbolのビット

enumerate the symbol character set.

Symbol character sets have a special meaning. If the symbol bit (31) is set,
 and the font file contains a 'cmap' subtable for platform of 3 and encoding ID of 1,
 then all of the characters in the Unicode range 0xF000 - 0xF0FF (inclusive) will be used to enumerate the symbol character set. 

If the bit is not set, any characters present in that range will not be enumerated as a symbol character set. 

OS/2 - OS/2 and Windows metrics table specification (version 4) - Typography | Microsoft Docs

http://www.high-logic.com/fontcreator/manual/index.html?unicodevssymbol.html