feldgrau23, Im sorry to say this, but the Pz D should have all the dampers. They can be hard to spot in some photos, but they are there. If you check out the museum photo about half way down the page, you will see the dampers. Here is the link:
http://www.wwiivehicles.com/html/germany/pzkpfw_iv_photos.html
The dampers that the Tamiya Pz IV D has are incorrect in shape though. Here is another photo of a Pz IV G, but it still has the correct dampers.
http://tanxheaven.com/dg/panzer4Gdg/panzer4Gdg-008.jpg
I believe it was the Pz C and before that did not have the dampers. You should be able to easily tell thought because the D had a new gun mantel shield and had extra support around the tow hitch in the back.