This will also affect the Wine RC compiler as well.
Even the Windows RC compiler emits an invalid template in that case. I just tested with this .rc file:
---- #include <windows.h>
MSGBOXFONT DIALOGEX 0,0,128,128 STYLE WS_SYSMENU|WS_CAPTION|WS_POPUP|DS_SETFONT|DS_MODALFRAME CAPTION "Test" FONT 0x7fff,"",0,0,0 BEGIN LTEXT "WINE dialog test.",-1,0,0,128,128 END ----
RC version is 6.1.6723.1
It would complain that the font name was missing if I'd give it only "FONT 0x7fff". And it emits the 6 bytes for the '"",0,0,0' part (which it shouldn't)