I just did this softroot last week and there are only a few things you need to know that are not clear. Otherwise, the nookLibrary turns the crap data sort system into something from the 21st century; well worth the effort. Your version serial number has no issues.
First, follow the instructions for the softroot absolutely. For example, you might wonder if you need to delete the first signed data file from the internal card before you add the external SD card with the 2.4.1 data file. It deletes itself. Second, after rooting you will have the new application launcher and a few apps; don't do anything untill you REBOOT the nook. It appears to be working and done, but it isn't. You hold down any of the icons for a second or two to get to the add-delete menu options.
Now you have to go through the mess to get the nookLibrary app installed. This means you have to get the ADB over USB app from nookdev and install it on your computer. It comes, missing the main ingredient so you need to start it and download the 1.5 application and set all the computer shell settings and such as indicated on the
info page.
No you need to get Android Commander
here and get it to talk to ADB. When you are finally there, you need to have the nookLibrary app from
here and finally, with you nook plugged in, you have to figure out how to get Commander to install the nookLibrary (rather tricky) as an update.
I'll keep an eye on this page so let me know if you follow through and I will add more detailed steps for the last part. It is well worth it.