Returning Phone, Need Help

[Wifi Guy]

Hi everyone. I am returning my mogul to sprint within my 30 days trial. When I got it it came with winmo 6.0, and i followed the easy guide to upgrade (http://forum.ppcgeeks.com/showthread.php?t=17667) and flashed it with 6.1 cooked or something. I followed that guide step by step.

What I need to know now is what do I have to do to get the phone back to factory rom/settings? Do I have to relock the phone? I dont even really understand what locking/unlocking does, I just followed that guide. If anyone here can help me I would really appreciate it. Thanks.