This video shows that it doesent matter if Apple upgraded their iPhones from 3G to 3Gs, because using RedSn0w and UltraSn0w you can still pwn your phone with ease.
You can also see how to capture the IBEC and IBSS files, ensuring the future Jailbreak of iPhone 3Gs. All jokes aside , you really need to save those files, and here is a tutorial on how to do it, in case you missed it.