All Server and Enterprise versions will support SetupComplete.cmd.
But lower client SKUs like Home and Pro, will not work if they are OEM versions.
If you select a $OEM$ folder, WinNTSetup will copy
$$\Setup\Scripts\SetupComplete.cmd to \Windows\Setup\Scripts\SetupComplete.cmd.
After setup finished you can check the log file under: \Windows\Panther\UnattendGC\setupact.log.