Leopard image, flat packages

Been a while since I posted to the forum, hope everyone is doing well. Trying to use r405 to spin a Leopard image, running on a 10.5.8 machine. It's entirely possible I just missed it in the documentation so please tell me RTFM if needed but - at some point since r272 was a requirement for flat packages defined? I just rebuilt a bunch of custom setup pkgs to be flat, now they work with r405. But a few Apple created updates, necessary for Leopard, are not flat and are still making instadmg barf. AirPort Base Station Update 2010-001 (5.5.1) Front Row Update 2.1.7 Remote Desktop Client Update 3.3.2 The latest release of ARD still spits out a non-flat/old style pkg installer BTW...bugreport.apple.com that. I'm perfectly happy to re-package those updates but it seems a shade unnecessary, no? (Admittedly, this will probably be the last time I build Leopard images but this should work for backward compatibility support.)