They won't necessarily need to do dish or receiver replacements. I think the plan is to move the 72.5 SD locals to 119. 119 is getting freed up by the move of the MPEG-2 HD channels to the Ka Sats in MPEG-4.
They are employing a strategy similar to that with the R22. It's based on the HR2x machines. The hardware is so close that some believe that it's just a software crippled HR2x with a smaller hard drive.
That's not how Directv usually does it. I've had a few of these trials. When the period ends, you stop getting those channels unless you call to subscribe.