Typically, you have chosen a second application in which to record the archival code. You can choose to put it in the same application as the GUI in question.
Browse the class side of the GUI class (or part class or whichever class you generated archival code for).
I don't have an example handy, so I can only vaguely tell you what to look for. You will see methods (most of them private methods) with "part builder" names, as well as "calculate" or "generate" (although I think it's really "calculate"). The method categories may help you identify them all, but I don't remember.
Checking for the differences between the version which first includes the archival code and the one which doesn't would also be an effective way to identify what is the generated code.