This is most definitely just a sheet metal cover, there’s simply no space for the composites underneath or over the turret, plus this is an old AZ which in this case was traveling without its ERA even.
A tank like the Type 59 can survive all those (barring the SPG, this tank wasn’t hit with that), because none of them are AT weapons. VBIEDS aren’t penetrative, they will do burn and frag damage as seen on this tank, and it was indeed hit by an RPG, but an HE Round, that would likely have just torn off that metal plate, the rest of the damage on the tank is indicative of such a hit.
There was another case in which an AZ turret was hit by an SPG-7 AT round and it went clear through the front and then out the back. That’s an entirely different tank altogether, there are pictures available of that tank too.
Regardless, in the pictures I posted above, the second two are of an AZ with composite armor over the turret. So they did improve it, it’s likely a bolt on upgrade that can be attached at any time.
The other tank in question, the back of the turret is blown open.
View attachment 791820
Other damaged AZs:
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