I think this is already checked in CommonSettings.php or am I missing something ?

Looks like kind of C&P:

+if ($wgDevelEnvironment) {
 +  $wgCacheBuster = time();
 +} else {
 +  // This file is created and updated by deploytools2
 +  include_once("$IP/wgCacheBuster.php");
 +}

Does it have to be in 2 places ?