The smbfs kernel module do not honor uid, gid, file_mode and dir_mode supplied by user during mount. http://linux.bkbits.net:8080/linux-2.6/cset@41752f820crlhkG3FzR1EMmg1OxskA
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release.
Taking a closer look it appear RHEL3 does not have problem, for a couple of reasons. One, this is a patch to the UNIX capabilities code and that capability does not exist in the RHEL3 version. Secondly, it appears the uid, gid and mode are (at least initially) *always* set to the uid, gid and mode that are passed down from the mount. So I don't see how they are being ignored.
Closing based on last two comments.