I found it illogical to advertise unusable 8bit formats. But I did not cross check whether MS-Windows would do so.
Indeed, MS-Windows advertises both 8 and 16 bit formats. Jeff Zaroyko kindly supplied me with winetest results ran with WINETEST_INTERACTIVE=1 on MS-Windows Vista. The msacm test then displays all advertised formats.
However I've not tested whether MS-Windows actually converts the advertised 8 bit formats.
Regards, Jorg Hohle