samba - Jun 2002 - Winbind question: Is there a variable with UID (and one for GID)

I am setting up winbindd here, and I see the
standard entries in the smb.conf manual for %U / %G etc.  These refer
to the users name string.  Are there (undocumented?) variables for the 
(unix) numeric UID and GID.  

Thanks

Allan