Indeed, if you just rotate the top rear to front, that can add some weight on the hitch. But even that, I'm not sure. Isn't the counterweight supposed to compensate for a good amount of the arm's weight? If so, the rotating shouldn't modify much the balance on the tracks. In both cases, it seems that you can adjust the excavator's position accordingly, a good amount toward the rear ( if nose heavy), or a bit toward the front by putting the blade on the rear (if butt heavy).
Just thinking out loud, I'm not there and you know your gear.