I called a CS rep and asked if the OS was preinstalled, he said yes, I didn't think to ask him what "Linux 1.3 Shell" was, I did some searching, at some Linux sites, couldn't find this specific version. Looks like they are out of them for right now, he said they would be getting some more in soon. I was interested in it because it looked like a low priced and low hassle way to start into Linux. With the OS preinstalled I'm sure the hardware would be configured correctly and ready for the internet, but, then, you never know.
Edit: I think it's "Caldera Open Linux 1.3" is my closest guess.