AFAIK, while later hardware versions cannot run early firmware, the opposite is not true: early hardware versions can run the later firmware. (2.04 SP1 is as late as you would want though -- after that, the firmware seems to be buggy).
2.02 SP2 was the last firmware that allowed changing the model number (and hence, allowed the hack). In order to hack a later model, the firmware must first be downgraded to 2.02 SP2, model changed, then the firmware upgraded again before using the scope.
There is a hidden screen that will reveal the hardware version. Press Utility, then advance to page 3 of 3, then System Info. Now, to reveal the hidden screen:
Press Ch1 twice
Press Ch2 twice
Press Math once
Now the screen will show extra info, including the hardware version. H/W 58 is the later version that won't run properly on firmware 2.02. You could ask the seller to send you a picture of that screen.