I was able to download the ARD 3.5.2 Client and take the customisations from the generated custom client installer.
To do this you need to expand the Custom Installer to a directory somewhere (in this example I'll expand it to a directory on the desktop)
pkgutil --expand CustomClientInstaller.pkg ~/Desktop/CustomClientInstaller
Inside the expanded package, there are 3 files which are appended with "_entries" which seem to contain the customisations that are specified during the package generation process. So, we need to copy these to a temporary location...
cp ~/Desktop/CustomClientInstaller/RemoteDesktopClient.pkg/Scripts/Tools/*_entries ~/Desktop
Now, what we need to do is expand the ARD Client we just downloaded (3.5.2) and apply the customisations to it...
pkgutil --expand RemoteDesktopClient.pkg ~/Desktop/RemoteDesktopClient
cp ~/Desktop/*_entries ~/Desktop/RemoteDesktopClient/RemoteDesktopClient.pkg/Scripts/Tools
pkgutil --flatten ~/Desktop/RemoteDesktopClient CustomRemoteDesktopClient.pkg
You should now have an up-to-date customised ARD client. Note that I have not fully tested all of the options, such as creating users. It may be necessary to look at this post if the newly customised ARD client has problems creating a new user.
Hope that helps
If you have ssh access to the system, you can use the generic client install package, install it via ssh as discribed in the ARD Admin Guide ( http://images.apple.com/remotedesktop/pdf/ARD_Admin_Guide.pdf ), then use the information on the following page to configure the client via ssh.
Basically comes down to something like the following command:
sudo /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/k ickstart -activate -configure -access -on -restart -agent -privs -all -users <ShortName>