They started selling OTB 1.1.2 around week 42/43. If you're looking to only jailbreak (and not unlock) an OTB 1.1.2 phone, the process is exactly the same as one that's been updated to 1.1.2. You'll just need to downgrade to 1.1.1 to install Oktoprep. There are several guides on here that will explain how to do that.
There should be no difference. I would, however tell you to have the phone activated and working before doing anything. It just makes it easier.
Download the 1.1.2 Jailbreak.zip and the 1.1.1 ipsw software.
Hold the left shift key and left click restore (windows instructions)
Locate the 1.1.1 ipsw file and select.
Wait till the restore finishes and you rebooted and put your profile back on the phone.
Turn WiFi on (must have a wiFi internet connection available) and while in settings, verify (in the about section) your on firmware 1.1.1
Visit www.jailbreakme.com and install the installer app, following the instructions.
when Installer is added, open and go to Installs and look in Tweaks 1.1.1 and install OkToPrep
Now you are ready to update to 1.1.2 again (just click restore and iTunes should take care of it from there, and then launch the windows.bat file ( again, windows instructions) from the 1.1.2 Jailbreak .zip extracted files.
When it's done, you should be on 1.1.2 and have the installer app available.
Thanks guys... I've actually already gone through the process w/ my OTB 1.1.2. I was going to jailbreak another phone which is older than mine and wanted to make sure I do it correctly. Thanks 4 the help...