the Early Jagdtiger was the one with the Porche suspension,
then they ahd the Henshell Suspension ones later on and the late Jagdtiger had a machine gun on the engine deck
theres a Porche Jagdtiger at Bovinton tank musium England,(the only one left)
and theres a Henshell Jagdtiger at Aberdeen proving grounds US and at Kubinka Russia
try http://www.jagdtiger.de/index2.htm?http://www.jagdtiger.de/GermanTanks/PzIV-01.htm for photos of the Kubinka one
the Eduard barrel would fit as the Two Dragon top parts are the same and so is the Revell kit, and the Etch kit for the Revell kit would/should include the engine grills other little bits that you get with the Dragon kits