Microsoft Office 2003 Service Pack 1 (SP1) has been out since July 2004, so your organization probably has had time to test and deploy it and to incorporate it into your Office 2003 installations. What you might have overlooked is that Microsoft has also issued new policy template .adm files that make it easy to enforce new SP1 settings for Outlook and other Office programs. In addition, there are new .opa files, which the Office Resource Kit's Custom Installation Wizard (CIW) and Custom Maintenance Wizard (CMW) use to set user defaults that you don't want to mandate through Group Policy Objects (GPOs). The real bonus, though, is that Microsoft has developed a pair of Microsoft Excel worksheets that list all the policy and UI options in the SP1 versions of all the Office programs. You can use these worksheets to help decide which settings you want to deploy as default user preferences by using the CIW or CMW and which settings you want to lock down by using GPOs. All these resources are available in a single download from the Microsoft Web site (see the first URL below).
When you download and run the executable, you can choose to extract the policy template files to any folder on your system. Move the extracted .opa files to the \program files\orktools\ork11\tools\shared folder on the machine on which you run the CIW and CMW to build your deployment .mst transform files and maintenance .cmw files. (You might want to back up your original .opa files to another location before you put the new files in place.) From that point on, the CIW and CMW will use the new settings collection from the .opa files.
To replace the policy templates, you first need to remove the old Office 2003 policy templates. In the Group Policy Editor, right-click Administrative Templates, then choose Add/Remove Templates. Choose to remove all the Office 2003 templates. (You might then want to copy them out of the \windows\inf or \winnt\inf folder--whichever is appropriate on your system--to a backup location.) Copy the new .adm files to the same \inf folder. You can then add the Outlk11.adm template for Outlook 2003, for example, to the templates displayed in the Group Policy Editor.
As far as the Excel worksheets go, each worksheet lets you browse the available options in a different way. The Office 2003 UI Options.xls worksheet walks through not just the settings that users can configure in Tools, Options, but also lists settings available on some other menus. A separate column lists the registry value associated with each setting (when available), whereas other columns list default and other allowable registry values. Similarly, the Office 2003 Group Policies.xls worksheet shows all the available Group Policy and CIW or CMW settings, arranged in the same order that you see them in the hierarchy under Administrative Templates in the Group Policy Editor. In both spreadsheets, the Policy? and CIW? columns tell you which options you can configure through GPOs and with the CIW or CMW. The New? and SP1? columns tell you which feature settings are new in Office 2003 itself and which are new in Office 2003 SP1. Excel's AutoFilter feature makes it easy to filter the spreadsheet to show just the SP1 changes. (There are no new UI settings listed for Outlook for SP1.) But before you do that, I suggest that you color-code each Office product (or at least the ones you're interested in) so that you know what you're looking at in the filter. Filtering for all new SP1 settings hides the row that tells you which product you're looking at. For example, Outlook 2003's settings are in rows 1016 through 1679 in the Office 2003 Group Policies.xls worksheet. If you select those rows, then apply a yellow fill color to them, when you filter only SP1 items, you'll know that the yellow ones belong to Outlook.
To activate the AutoFilter feature, click anywhere in row 1 of the worksheet, then choose Data, Filter, AutoFilter. To show only SP1 items, click the down arrow in the column labeled SP1? (column M in the Office 2003 Group Policies.xls file) and choose Yes. You should see several Outlook settings that can now be configured through GPOs (although not by using the CIW or CMW). For example, the Level1Add value for blocking more types of file attachments in Outlook items is available in SP1 as a policy setting that controls that value in the HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Office\11.0\Outlook\Security registry entry. It works just like Level1Remove, taking a semicolon-delimited list of file-type extensions that you don't want users to be able to access in email messages. With these two spreadsheets, you can get a much clearer idea of what settings are under administrative control than you'd get clicking through the UI or the Group Policy Editor. Don't forget to examine the general Office settings, where you'll find options that affect Outlook's integration with Windows SharePoint Services and the behavior of WordMail (i.e., Word as Outlook's email editor).
Office 2003 SP1 Policy Template Files
Office 2003 Resource Kit--Managing Users' Configurations by Policy