A friend of mine runs Castoff which does resin upgrades for popular tanks including one for the supposedly Tamiya Mk5 Chieftain. His kits puts all the right stuff that's missing, correct NBC pack, barrel with the shroud on the end etc. I was showing him some pictures of our Mk 3s we had for year in Berlin with the .50 sticking out of the side and I asked him if the Tamiya model has the welded oval on the turret and he said it didn't. He wants to include a resin oval with his kit for people to stick on. He asked me if ll the Chieftains were the same and I told him yes but now I'm not sure. I know some were built as Mk 5's but did they have this filled in on construction? It would have cost a fortune to change the cast methinks. Any clues?