http://bugs.winehq.org/show_bug.cgi?id=30713
--- Comment #1 from Dan Kegel dank@kegel.com 2012-05-17 15:25:36 CDT --- Evidence that the installed file is 64 bit:
$ file /home/dank/.wine/drive_c/windows/syswow64/mfc100.dll /home/dank/.wine/drive_c/windows/syswow64/mfc100.dll: PE32+ executable (DLL) (console) x86-64, for MS Windows