Good.
The Museum’s exhibit was built as a Panzer IV Ausf D and was originally armed with the short 7.5cm KwK 37 gun. The Museum’s vehicle was further upgraded by the addition of 30mm extra armour on the superstructure front and 20mm armour on the hull and superstructure sides before it had left the factory. In 1943 additional armour was put on the front and the original 75mm KwK L/24 replaced with the KwK 40 L/43 . The tank was further improved by the installation of spaced armour (or schurzen) around the sides and back of the turret.
The Nationalsozialistisches Kraftfahrerkorps, (NSKK or National Socialist Motor Vehicle Training Corps) used the Tank Museum’s Panzer IV Aus D as a driver-training tank; nothing is known of its earlier military career
(From Museum website)