Searching the forums it appears this problem is not new but perhaps it has been assumed to no longer be an issue.  Tonight I tried to edit a file served by Samba with XEmacs 21.4.20, 21.4.21, and 21.5-b28.  Each attempt and each version yielded the same result.  I.e. XEmacs would open the file read-only ignoring true permissions.  After opening the file read-only, I would M-X toggle-read-only, make my changes, and save.  This work around unfortunately does not help if the file does not exist as XEmacs refuses to make files in directories served by Samba.  It seems to think that all directories are read-only.

For what it is worth, this is not a problem with GNU Emacs 22.1.  (I've been using XEmacs for years and would hate to switch now though :( )

If there is any more information that would be helpful or any work around please contact me.