That's a bug with copy_a_file
As a workaround, you can call change_owner() and change_mode() in /opt/SUNWjass/Finish/install-templates.fin (or a new .fin script you write yourself)
For example:
<div class="pre"><pre>
copy_files "${JASS_FILE_LIST}"
change_owner root:root /path/to/some/file
change_mode 400 root:root /path/to/some/file
</pre></div>