Not at all. The Panther required an entirely new hull and turret. The engine and transmission were totally new. The suspension is totally new.
The tank described above has some new parts and some new layout for its armor. But, other than the turret and gun it is really still a Pz IV. The suspension has not changed. The track is a new design but this is not a big engineering investment. The hull is still mostly the same. The engine is modified but not a new engine. The transmission is still the same again with modifications.
These modifications require alot less engineering and design than a whole new vehicle does. Thus, it is not a "Panther in a different dress."