Since it has a short gun, that must be the Ausf. D...?

Hmm... Let's see.

Hull-mounted MG? Check.
External gun mantlet? Check.
Snub nose 5cm gun? Check.

Yeah, I'd say it's the Ausf. D.

While the Ausf. A and Ausf. D are very similar in outward appearance, the clear indicator it's the latter variant is the existence of the external gun mantlet. Ausf. B and C, on the other hand, lacks the hull-mounted MG which is replaced by a covered gun port.

AdventZero said:

Hmm... Let's see.

Hull-mounted MG? Check.
External gun mantlet? Check.
Snub nose 5cm gun? Check.

Yeah, I'd say it's the Ausf. D.

While the Ausf. A and Ausf. D are very similar in outward appearance, the clear indicator it's the latter variant is the existence of the external gun mantlet. Ausf. B and C, on the other hand, lacks the hull-mounted MG which is replaced by a covered gun port.

7.5cm, not 5cm. You also missed Ausf. E and F1, which satisfy all your features above. This one is Ausf. D because of its stepped frontal armour as well as old style driver's visor.