Just setup my Prime. Received from Amazon yesterday. It came with 20120405 f/w. I got the CC from Comcast just now. I upgraded the f/w to 20130117, followed the instructions and I'm in business.
I had been using an HDHR for a number of years, wasn't sure if I needed to uninstall the software to transition to the new box or not, so I left it as-is, and just unplugged the old unit. The software shows the old tuners, but status is 'Not found'.
Anyway, I walked through the process per the SD website and it just works. I just have Limited Basic so that may have simplified the setup (provisioning?) in my case. Recording an HD channel as I type this.