You can install the RemoteDesktop.mpkg on an Apple Remote Desktop 2 client, but the Installer does not provide feedback to indicate a successful installation. (Installation of this packages may be advantageous when configuring multiple administration computers or switching to another computer.)
Because this particular package stops (kills) the Apple Remote Desktop 2 agent process after successful installation, the lack of notification should be considered normal behavior.
To verify successful installation of the admin application on the client, go to the client and open the application.